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Liu X, Deng Y, Liang Z, Qiao D, Zhang W, Wang M, Li F, Liu J, Wu Y, Chen G, Liu Y, Tan W, Xing J, Huang W, Zhao D, Li Y. The alteration of the structure and macroscopic mechanical response of porcine patellar tendon by elastase digestion. Front Bioeng Biotechnol 2024; 12:1374352. [PMID: 38694621 PMCID: PMC11061363 DOI: 10.3389/fbioe.2024.1374352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Accepted: 04/01/2024] [Indexed: 05/04/2024] Open
Abstract
Background: The treatment of patellar tendon injury has always been an unsolved problem, and mechanical characterization is very important for its repair and reconstruction. Elastin is a contributor to mechanics, but it is not clear how it affects the elasticity, viscoelastic properties, and structure of patellar tendon. Methods: The patellar tendons from six fresh adult experimental pigs were used in this study and they were made into 77 samples. The patellar tendon was specifically degraded by elastase, and the regional mechanical response and structural changes were investigated by: (1) Based on the previous study of elastase treatment conditions, the biochemical quantification of collagen, glycosaminoglycan and total protein was carried out; (2) The patellar tendon was divided into the proximal, central, and distal regions, and then the axial tensile test and stress relaxation test were performed before and after phosphate-buffered saline (PBS) or elastase treatment; (3) The dynamic constitutive model was established by the obtained mechanical data; (4) The structural relationship between elastin and collagen fibers was analyzed by two-photon microscopy and histology. Results: There was no statistical difference in mechanics between patellar tendon regions. Compared with those before elastase treatment, the low tensile modulus decreased by 75%-80%, the high tensile modulus decreased by 38%-47%, and the transition strain was prolonged after treatment. For viscoelastic behavior, the stress relaxation increased, the initial slope increased by 55%, the saturation slope increased by 44%, and the transition time increased by 25% after enzyme treatment. Elastin degradation made the collagen fibers of patellar tendon become disordered and looser, and the fiber wavelength increased significantly. Conclusion: The results of this study show that elastin plays an important role in the mechanical properties and fiber structure stability of patellar tendon, which supplements the structure-function relationship information of patellar tendon. The established constitutive model is of great significance to the prediction, repair and replacement of patellar tendon injury. In addition, human patellar tendon has a higher elastin content, so the results of this study can provide supporting information on the natural properties of tendon elastin degradation and guide the development of artificial patellar tendon biomaterials.
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Affiliation(s)
- Xiaoyun Liu
- National Key Discipline of Human Anatomy, Guangdong Provincial Key Laboratory of Medical Biomechanics, Guangdong Engineering Research Center for Translation of Medical 3D Printing Application, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
- Institute of Biomedical Engineering, Shenzhen Bay Laboratory, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Yuping Deng
- National Key Discipline of Human Anatomy, Guangdong Provincial Key Laboratory of Medical Biomechanics, Guangdong Engineering Research Center for Translation of Medical 3D Printing Application, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
- Institute of Biomedical Engineering, Shenzhen Bay Laboratory, Peking University Shenzhen Graduate School, Shenzhen, China
- Department of Orthopedics and Traumatology, Integrated Hospital of Traditional Chinese Medicine, Southern Medical University, Guangzhou, China
| | - Zeyu Liang
- National Key Discipline of Human Anatomy, Guangdong Provincial Key Laboratory of Medical Biomechanics, Guangdong Engineering Research Center for Translation of Medical 3D Printing Application, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Dan Qiao
- Department of Pathology, Sir Run Run Shaw Hospital, Zhejiang University, Hangzhou, Zhejiang, China
| | - Wentian Zhang
- National Key Discipline of Human Anatomy, Guangdong Provincial Key Laboratory of Medical Biomechanics, Guangdong Engineering Research Center for Translation of Medical 3D Printing Application, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
- The School of Basic Medical Sciences, Fujian Medical University, Fujian, China
| | - Mian Wang
- National Key Discipline of Human Anatomy, Guangdong Provincial Key Laboratory of Medical Biomechanics, Guangdong Engineering Research Center for Translation of Medical 3D Printing Application, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
- Institute of Biomedical Engineering, Shenzhen Bay Laboratory, Peking University Shenzhen Graduate School, Shenzhen, China
- Department of Orthopaedics, Pingshan General Hospital of Southern Medical University, Shenzhen, China
| | - Feifei Li
- National Key Discipline of Human Anatomy, Guangdong Provincial Key Laboratory of Medical Biomechanics, Guangdong Engineering Research Center for Translation of Medical 3D Printing Application, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Jiannan Liu
- National Key Discipline of Human Anatomy, Guangdong Provincial Key Laboratory of Medical Biomechanics, Guangdong Engineering Research Center for Translation of Medical 3D Printing Application, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Yaobing Wu
- National Key Discipline of Human Anatomy, Guangdong Provincial Key Laboratory of Medical Biomechanics, Guangdong Engineering Research Center for Translation of Medical 3D Printing Application, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Guangxin Chen
- Medical Image College, Mudanjiang Medical University, Mudanjiang, Heilongjiang, China
| | - Yan Liu
- Department of Anatomy, Gannan Healthcare Vocational College, Ganzhou, China
| | - Wenchang Tan
- Institute of Biomedical Engineering, Shenzhen Bay Laboratory, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Jian Xing
- Medical Image College, Mudanjiang Medical University, Mudanjiang, Heilongjiang, China
| | - Wenhua Huang
- National Key Discipline of Human Anatomy, Guangdong Provincial Key Laboratory of Medical Biomechanics, Guangdong Engineering Research Center for Translation of Medical 3D Printing Application, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
- Department of Orthopedics and Traumatology, Integrated Hospital of Traditional Chinese Medicine, Southern Medical University, Guangzhou, China
- Guangdong Medical Innovation Platform for Translation of 3D Printing Application, The Third Affiliated Hospital of Southern Medical University, Guangzhou, China
| | - Dongliang Zhao
- Institute of Biomedical Engineering, Shenzhen Bay Laboratory, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Yanbing Li
- National Key Discipline of Human Anatomy, Guangdong Provincial Key Laboratory of Medical Biomechanics, Guangdong Engineering Research Center for Translation of Medical 3D Printing Application, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
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Jones DL, Hallström GF, Jiang X, Locke RC, Evans MK, Bonnevie ED, Srikumar A, Leahy TP, Nijsure MP, Boerckel JD, Mauck RL, Dyment NA. Mechanoepigenetic regulation of extracellular matrix homeostasis via Yap and Taz. Proc Natl Acad Sci U S A 2023; 120:e2211947120. [PMID: 37216538 PMCID: PMC10235980 DOI: 10.1073/pnas.2211947120] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 04/20/2023] [Indexed: 05/24/2023] Open
Abstract
Cells integrate mechanical cues to direct fate specification to maintain tissue function and homeostasis. While disruption of these cues is known to lead to aberrant cell behavior and chronic diseases, such as tendinopathies, the underlying mechanisms by which mechanical signals maintain cell function are not well understood. Here, we show using a model of tendon de-tensioning that loss of tensile cues in vivo acutely changes nuclear morphology, positioning, and expression of catabolic gene programs, resulting in subsequent weakening of the tendon. In vitro studies using paired ATAC/RNAseq demonstrate that the loss of cellular tension rapidly reduces chromatin accessibility in the vicinity of Yap/Taz genomic targets while also increasing expression of genes involved in matrix catabolism. Concordantly, the depletion of Yap/Taz elevates matrix catabolic expression. Conversely, overexpression of Yap results in a reduction of chromatin accessibility at matrix catabolic gene loci, while also reducing transcriptional levels. The overexpression of Yap not only prevents the induction of this broad catabolic program following a loss of cellular tension, but also preserves the underlying chromatin state from force-induced alterations. Taken together, these results provide novel mechanistic details by which mechanoepigenetic signals regulate tendon cell function through a Yap/Taz axis.
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Affiliation(s)
- Dakota L. Jones
- Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA19104
| | - Grey F. Hallström
- Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA19104
| | - Xi Jiang
- Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA19104
| | - Ryan C. Locke
- Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA19104
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA19104
- Translational Musculoskeletal Research Center, Corporal Michael Crescenz Veterans Affairs Medical Center, Philadelphia, PA19104
| | - Mary Kate Evans
- Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA19104
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA19104
| | - Edward D. Bonnevie
- Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA19104
- Translational Musculoskeletal Research Center, Corporal Michael Crescenz Veterans Affairs Medical Center, Philadelphia, PA19104
| | - Anjana Srikumar
- Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA19104
| | - Thomas P. Leahy
- Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA19104
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA19104
| | - Madhura P. Nijsure
- Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA19104
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA19104
- Center for Engineering Mechanobiology, University of Pennsylvania, Philadelphia, PA19104
| | - Joel D. Boerckel
- Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA19104
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA19104
- Center for Engineering Mechanobiology, University of Pennsylvania, Philadelphia, PA19104
| | - Robert L. Mauck
- Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA19104
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA19104
- Translational Musculoskeletal Research Center, Corporal Michael Crescenz Veterans Affairs Medical Center, Philadelphia, PA19104
- Center for Engineering Mechanobiology, University of Pennsylvania, Philadelphia, PA19104
| | - Nathaniel A. Dyment
- Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA19104
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA19104
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Dixon G, Potter S, Shapiro MS, Santa Maria E, Schmidt D, Santa Maria D. Profound Healing of a Quadriceps Tendon Tear Following Intratendinous Minimally Invasive Platelet-Rich Plasma Injection. Curr Sports Med Rep 2023; 22:164-167. [PMID: 37141610 DOI: 10.1249/jsr.0000000000001062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Affiliation(s)
- Grant Dixon
- Department of Rehabilitation Medicine, Long School of Medicine, University of Texas Health San Antonio, San Antonio, TX
| | - Steven Potter
- Department of Rehabilitation Medicine, Long School of Medicine, University of Texas Health San Antonio, San Antonio, TX
| | - Mark S Shapiro
- Department of Cellular and Integrative Physiology, Long School of Medicine, University of Texas Health San Antonio, San Antonio, TX
| | - Emma Santa Maria
- University of the Incarnate Word, School of Professional Studies, San Antonio, TX
| | - David Schmidt
- Sports Medicine Associates of San Antonio, San Antonio, TX
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Prusa G, Bauer L, Santos I, Thorwächter C, Woiczinski M, Kistler M. Strain evaluation of axially loaded collateral ligaments: a comparison of digital image correlation and strain gauges. Biomed Eng Online 2023; 22:13. [PMID: 36774524 PMCID: PMC9922447 DOI: 10.1186/s12938-023-01077-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Accepted: 02/03/2023] [Indexed: 02/13/2023] Open
Abstract
The response of soft tissue to loading can be obtained by strain assessment. Typically, strain can be measured using electrical resistance with strain gauges (SG), or optical sensors based on the digital image correlation (DIC), among others. These sensor systems are already established in other areas of technology. However, sensors have a limited range of applications in medical technology due to various challenges in handling human soft materials. The aim of this study was to compare directly attached foil-type SG and 3D-DIC to determine the strain of axially loaded human ligament structures. Therefore, the medial (MCL) and lateral (LCL) collateral ligaments of 18 human knee joints underwent cyclic displacement-controlled loading at a rate of 20 mm/min in two test trials. In the first trial, strain was recorded with the 3D-DIC system and the reference strain of the testing machine. In the second trial, strain was additionally measured with a directly attached SG. The results of the strain measurement with the 3D-DIC system did not differ significantly from the reference strain in the first trial. The strains assessed in the second trial between reference and SG, as well as between reference and 3D-DIC showed significant differences. This suggests that using an optical system based on the DIC with a given unrestricted view is an effective method to measure the superficial strain of human ligaments. In contrast, directly attached SGs provide only qualitative comparable results. Therefore, their scope on human ligaments is limited to the evaluation of changes under different conditions.
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Affiliation(s)
- Gwendolin Prusa
- Department of Orthopaedics and Trauma Surgery, Musculoskeletal University Center Munich (MUM), University Hospital, LMU Munich, Marchioninistraße 15, 81377, Munich, Germany.
| | - Leandra Bauer
- grid.5252.00000 0004 1936 973XDepartment of Orthopaedics and Trauma Surgery, Musculoskeletal University Center Munich (MUM), University Hospital, LMU Munich, Marchioninistraße 15, 81377 Munich, Germany
| | - Inês Santos
- grid.5252.00000 0004 1936 973XDepartment of Orthopaedics and Trauma Surgery, Musculoskeletal University Center Munich (MUM), University Hospital, LMU Munich, Marchioninistraße 15, 81377 Munich, Germany
| | - Christoph Thorwächter
- grid.5252.00000 0004 1936 973XDepartment of Orthopaedics and Trauma Surgery, Musculoskeletal University Center Munich (MUM), University Hospital, LMU Munich, Marchioninistraße 15, 81377 Munich, Germany
| | - Matthias Woiczinski
- grid.5252.00000 0004 1936 973XDepartment of Orthopaedics and Trauma Surgery, Musculoskeletal University Center Munich (MUM), University Hospital, LMU Munich, Marchioninistraße 15, 81377 Munich, Germany
| | - Manuel Kistler
- grid.5252.00000 0004 1936 973XDepartment of Orthopaedics and Trauma Surgery, Musculoskeletal University Center Munich (MUM), University Hospital, LMU Munich, Marchioninistraße 15, 81377 Munich, Germany
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5
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Biological and Mechanical Factors and Epigenetic Regulation Involved in Tendon Healing. Stem Cells Int 2023; 2023:4387630. [PMID: 36655033 PMCID: PMC9842431 DOI: 10.1155/2023/4387630] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 12/18/2022] [Accepted: 12/28/2022] [Indexed: 01/11/2023] Open
Abstract
Tendons are an important part of the musculoskeletal system. Connecting muscles to bones, tendons convert force into movement. Tendon injury can be acute or chronic. Noticeably, tendon healing requires a long time span and includes inflammation, proliferation, and remodeling processes. The mismatch between endogenous and exogenous healing may lead to adhesion causing further negative effects. Management of tendon injuries and complications such as subsequent adhesion formation are still challenges for clinicians. Due to numerous factors, tendon healing is a complex process. This review introduces the role of various biological and mechanical factors and epigenetic regulation processes involved in tendon healing.
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6
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Citro V, Clerici M, Boccaccini AR, Della Porta G, Maffulli N, Forsyth NR. Tendon tissue engineering: An overview of biologics to promote tendon healing and repair. J Tissue Eng 2023; 14:20417314231196275. [PMID: 37719308 PMCID: PMC10501083 DOI: 10.1177/20417314231196275] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 08/06/2023] [Indexed: 09/19/2023] Open
Abstract
Tendons are dense connective tissues with a hierarchical polarized structure that respond to and adapt to the transmission of muscle contraction forces to the skeleton, enabling motion and maintaining posture. Tendon injuries, also known as tendinopathies, are becoming more common as populations age and participation in sports/leisure activities increases. The tendon has a poor ability to self-heal and regenerate given its intrinsic, constrained vascular supply and exposure to frequent, severe loading. There is a lack of understanding of the underlying pathophysiology, and it is not surprising that disorder-targeted medicines have only been partially effective at best. Recent tissue engineering approaches have emerged as a potential tool to drive tendon regeneration and healing. In this review, we investigated the physiochemical factors involved in tendon ontogeny and discussed their potential application in vitro to reproduce functional and self-renewing tendon tissue. We sought to understand whether stem cells are capable of forming tendons, how they can be directed towards the tenogenic lineage, and how their growth is regulated and monitored during the entire differentiation path. Finally, we showed recent developments in tendon tissue engineering, specifically the use of mesenchymal stem cells (MSCs), which can differentiate into tendon cells, as well as the potential role of extracellular vesicles (EVs) in tendon regeneration and their potential for use in accelerating the healing response after injury.
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Affiliation(s)
- Vera Citro
- School of Pharmacy and Bioengineering, Keele University, Stoke-on-Trent, Staffordshire, UK
- Department of Materials Science and Engineering, Institute of Biomaterials University of Erlangen-Nuremberg, Cauerstrasse 6, Erlangen, Germany
| | - Marta Clerici
- School of Pharmacy and Bioengineering, Keele University, Stoke-on-Trent, Staffordshire, UK
- Department of Medicine, Surgery and Dentistry, University of Salerno, via S. Allende, Baronissi, Salerno, Italy
| | - Aldo R. Boccaccini
- Department of Materials Science and Engineering, Institute of Biomaterials University of Erlangen-Nuremberg, Cauerstrasse 6, Erlangen, Germany
| | - Giovanna Della Porta
- Department of Medicine, Surgery and Dentistry, University of Salerno, via S. Allende, Baronissi, Salerno, Italy
- Interdepartmental Centre BIONAM, University of Salerno, via Giovanni Paolo I, Fisciano, Salerno, Italy
| | - Nicola Maffulli
- School of Pharmacy and Bioengineering, Keele University, Stoke-on-Trent, Staffordshire, UK
- Department of Medicine, Surgery and Dentistry, University of Salerno, via S. Allende, Baronissi, Salerno, Italy
- Department of Trauma and Orthopaedic Surgery, University Hospital ‘San Giovanni di Dio e Ruggi D’Aragona’, Salerno, Italy
| | - Nicholas R. Forsyth
- School of Pharmacy and Bioengineering, Keele University, Stoke-on-Trent, Staffordshire, UK
- Vice Principals’ Office, University of Aberdeen, Kings College, Aberdeen, UK
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7
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Stress Shielding of Ligaments Using Nonabsorbable Suture Augmentation May Influence the Biology of Ligament Healing. J Hand Surg Am 2022; 47:275-278. [PMID: 34716057 DOI: 10.1016/j.jhsa.2021.09.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 07/31/2021] [Accepted: 09/17/2021] [Indexed: 02/02/2023]
Abstract
Nonabsorbable suture augmentation of ligament reconstruction has seen an increase in use over the past several years with the goal of protecting the newly reconstructed ligament while allowing early rehabilitation for a potential earlier return to activity and sport. By spanning the joint with a durable nonabsorbable suture, this construct shares the stress and load seen by the reconstructed ligament, thereby protecting it from forces that could result in an early failure during the early ligamentization phase of the tendon graft. However, stress shielding of the ligament via nonabsorbable suture augmentation is also a double-edged sword, as a reduction in the stress and load seen by the ligament during this healing phase may ultimately have an impact on the final strength and composition of the reconstructed ligament. Although the long-term effects of this stress shielding have yet to be studied or reported in human subjects, multiple biomechanical and animal studies have demonstrated overall changes in architecture, tensile strength, and mechanical properties of a stress-shielded autograft ligament reconstruction.
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8
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Scleraxis and Collagen I Expression Increase Following Pilot Isometric Loading Experiments in a Rodent Model of Patellar Tendinopathy. Matrix Biol 2022; 109:34-48. [DOI: 10.1016/j.matbio.2022.03.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 02/23/2022] [Accepted: 03/21/2022] [Indexed: 11/19/2022]
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Wu SY, Kim W, Kremen TJ. In Vitro Cellular Strain Models of Tendon Biology and Tenogenic Differentiation. Front Bioeng Biotechnol 2022; 10:826748. [PMID: 35242750 PMCID: PMC8886160 DOI: 10.3389/fbioe.2022.826748] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 01/17/2022] [Indexed: 11/19/2022] Open
Abstract
Research has shown that the surrounding biomechanical environment plays a significant role in the development, differentiation, repair, and degradation of tendon, but the interactions between tendon cells and the forces they experience are complex. In vitro mechanical stimulation models attempt to understand the effects of mechanical load on tendon and connective tissue progenitor cells. This article reviews multiple mechanical stimulation models used to study tendon mechanobiology and provides an overview of the current progress in modelling the complex native biomechanical environment of tendon. Though great strides have been made in advancing the understanding of the role of mechanical stimulation in tendon development, damage, and repair, there exists no ideal in vitro model. Further comparative studies and careful consideration of loading parameters, cell populations, and biochemical additives may further offer new insight into an ideal model for the support of tendon regeneration studies.
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Affiliation(s)
- Shannon Y. Wu
- David Geffen School of Medicine at UCLA, Los Angeles, CA, United States
| | - Won Kim
- Department of Rehabilitation Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea
| | - Thomas J. Kremen
- Department of Orthopaedic Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States
- *Correspondence: Thomas J. Kremen Jr,
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Ebrahimi M, Mohammadi A, Ristaniemi A, Stenroth L, Korhonen RK. The effect of different preconditioning protocols on repeatability of bovine ACL stress-relaxation response in tension. J Mech Behav Biomed Mater 2019; 90:493-501. [DOI: 10.1016/j.jmbbm.2018.10.041] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 10/26/2018] [Accepted: 10/31/2018] [Indexed: 12/17/2022]
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Chen CH, Lin YH, Chen CH, Wang YH, Yeh ML, Cheng TL, Wang CZ. Transforming growth factor beta 1 mediates the low-frequency vertical vibration enhanced production of tenomodulin and type I collagen in rat Achilles tendon. PLoS One 2018; 13:e0205258. [PMID: 30307981 PMCID: PMC6181323 DOI: 10.1371/journal.pone.0205258] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 09/22/2018] [Indexed: 11/19/2022] Open
Abstract
Vertical vibration (VV) is a whole-body vibration with mechanical loading that commonly used in rehabilitation and sports training to increase athlete muscle strength. Our previous study showed that low-magnitude, low-frequency VV at 8 Hz and 10 Hz increased myoblast myogenesis. Herein, we investigated whether a VV frequency at low-frequency 5-10 Hz has anabolic effects on tenocytes and improves tendon stiffness. In primary tenocytes, 10 Hz VV treatment increased the tenogenic marker gene expression of tenomodulin and extracellular matrix type I collagen but decreased decorin expression. qPCR and Enzyme-Linked Immunosorbent Assay (ELISA) results showed that TGF-β1 expression was increased in tenocytes after 3 days of 10 Hz VV treatment in vitro and in Achilles tendons after 3 weeks in vivo. Tenomodulin expression and Achilles tendon stiffness were significantly increased in Achilles tendons after 3 weeks in vivo. We also showed that the TGF-β1 receptor inhibitor SB431542 (10 μM) decreased the expression of tenomodulin and type I collagen but increased the decorin expression in tenocytes. These results indicated that the 10 Hz VV stimulated anabolic effects in tenocytes by increasing TGF-β1 expression that subsequently increases the expression of tenomodulin and type I collagen, and increased the Achilles tendon stiffness. This study provides insight into the low-frequency 10 Hz VV treatment improves tendon properties and can minimizes the risk of ligament/tendon reinjure during rehabilitation.
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Affiliation(s)
- Chia-Hsin Chen
- Department of Physical Medicine and Rehabilitation, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan
- Department of Physical Medicine and Rehabilitation, Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
- Orthopaedic Research Center, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Yi-Hsiung Lin
- Orthopaedic Research Center, Kaohsiung Medical University, Kaohsiung, Taiwan
- Department of Physiology, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
- Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Chung-Hwan Chen
- Orthopaedic Research Center, Kaohsiung Medical University, Kaohsiung, Taiwan
- Department of Orthopaedics, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
- Department of Orthopedics, Kaohsiung Municipal Ta-Tung Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
- Division of Adult Reconstruction Surgery, Department of Orthopedics, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Yan-Hsiung Wang
- Orthopaedic Research Center, Kaohsiung Medical University, Kaohsiung, Taiwan
- School of Dentistry, Kaohsiung Medical University, Kaohsiung, Taiwan
- Department of Medical Research, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Ming-Long Yeh
- Department of Biomedical Engineering, National Cheng Kung University, No.1 University Road, Tainan City, Taiwan
| | - Tsung-Lin Cheng
- Orthopaedic Research Center, Kaohsiung Medical University, Kaohsiung, Taiwan
- Department of Physiology, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
- Department of Medical Research, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Chau-Zen Wang
- Orthopaedic Research Center, Kaohsiung Medical University, Kaohsiung, Taiwan
- Department of Physiology, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
- Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
- Department of Medical Research, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
- * E-mail:
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12
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Neville-Towle JD, Tan CJ, Parr WCH, Walsh WR, Johnson KA. Three-dimensional kinematics of the canine carpal bones imaged with computed tomography after ex vivo axial limb loading and palmar ligament transection. Vet Surg 2018; 47:861-871. [PMID: 30091145 PMCID: PMC6690077 DOI: 10.1111/vsu.12921] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Revised: 12/05/2017] [Accepted: 12/29/2017] [Indexed: 11/29/2022]
Abstract
OBJECTIVE To describe normal antebrachiocarpal joint kinematic motion during axial loading and to describe the effect of palmar radiocarpal ligament (PRL) and palmar ulnocarpal ligament (PUL) transection on this motion. SAMPLE POPULATION Ten forelimbs from 5 adult greyhound cadavers. METHODS Limbs were placed in a custom jig and computed tomography images of limbs were obtained in neutral and extended positions. The translation and rotation of the intermedioradiocarpal bone (RCB), ulnar carpal bone, and accessory carpal bone were described relative to the radius through rigid body motion analysis. Kinematic and load analysis was repeated after sequential transection of the PRL and the PUL. RESULTS Sagittal plane extension with a lesser component of valgus motion was found in all evaluated carpal bones. RCB supination was also detected during extension. Compared with the normal intact limb, transection of either or both the PRL and the PUL did not influence mean translation or rotation data or limb load. However, the transection of the PRL and the PUL increased the variance in rotation data compared with intact limb. CONCLUSION This study describes normal antebrachiocarpal kinematics as a foundation for determining carpal functional units. During axial loading, the PRL and the PUL may function to guide consistent motion in extension and flexion as well as pronation and supination. CLINICAL SIGNIFICANCE Three-dimensional carpal kinematic analyses may improve our understanding of carpal injury and facilitate the development of novel treatments techniques.
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Affiliation(s)
- Jack D Neville-Towle
- Sydney School of Veterinary Science, Faculty of Science, The University of Sydney, Sydney, Australia
| | - Christopher J Tan
- Sydney School of Veterinary Science, Faculty of Science, The University of Sydney, Sydney, Australia.,Surgical and Orthopaedic Research Laboratories, Prince of Wales Clinical School, Prince of Wales Hospital, University of New South Wales, Sydney, Australia
| | - William C H Parr
- Surgical and Orthopaedic Research Laboratories, Prince of Wales Clinical School, Prince of Wales Hospital, University of New South Wales, Sydney, Australia
| | - William R Walsh
- Surgical and Orthopaedic Research Laboratories, Prince of Wales Clinical School, Prince of Wales Hospital, University of New South Wales, Sydney, Australia
| | - Kenneth A Johnson
- Sydney School of Veterinary Science, Faculty of Science, The University of Sydney, Sydney, Australia
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Achilles tendon compositional and structural properties are altered after unloading by botox. Sci Rep 2017; 7:13067. [PMID: 29026107 PMCID: PMC5638919 DOI: 10.1038/s41598-017-13107-7] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Accepted: 09/18/2017] [Indexed: 02/07/2023] Open
Abstract
Tendon function and homeostasis rely on external loading. This study investigates the biological mechanisms behind tendon biomechanical function and how the mechanical performance is affected by reduced daily loading. The Achilles tendons of 16 weeks old female Sprague Dawley rats (n = 40) were unloaded for 5 weeks by inducing muscle paralysis with botulinum toxin injections in the right gastrocnemius and soleus muscles. The contralateral side was used as control. After harvest, the tendons underwent biomechanical testing to assess viscoelasticity (n = 30 rats) and small angle X-ray scattering to determine the structural properties of the collagen fibrils (n = 10 rats). Fourier transform infrared spectroscopy and histological staining (n = 10 rats) were performed to investigate the collagen and proteoglycan content. The results show that the stiffness increased in unloaded tendons, together with an increased collagen content. Creep and axial alignment of the collagen fibers were reduced. Stress-relaxation increased whereas hysteresis was reduced in response to unloading with botox treatment. Our findings indicate that altered matrix deposition relies on mechanical loading to reorganize the newly formed tissue, without which the viscoelastic behavior is impaired. The results demonstrate that reduced daily loading deprives tendons of their viscoelastic properties, which could increase the risk of injury.
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14
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YAMAMOTO N, NAKAMURA S. Relationships between the tensile strength and diameter of collagen fibrils isolated from mouse tail tendons. ACTA ACUST UNITED AC 2017. [DOI: 10.1299/jbse.16-00511] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
| | - Shun NAKAMURA
- Department of Mechanical Engineering, Ritsumeikan University
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15
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Chen K, Li P, Zhao H, Yan X, Ma Y. Effects of Tumor Necrosis Factor Inhibitor on Stress-Shielded Tendons. Orthopedics 2017; 40:49-55. [PMID: 27684081 DOI: 10.3928/01477447-20160926-03] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2016] [Accepted: 07/28/2016] [Indexed: 02/03/2023]
Abstract
Mechanical stress plays an important role in preserving the integrity of bone and ligament. Stress shielding reduces mechanical load on bone or tendons, resulting in tissue degradation. Previous studies showed that deterioration of the tendon structure during stress shielding is associated with elevated expression of tumor necrosis factor (TNF)-α. This study examined the therapeutic potential of the TNF inhibitor etanercept in preventing morphologic deterioration of the Achilles tendon after stress shielding. Rats (N=48) were exposed to stress shielding of the left Achilles tendon and treated with etanercept or phosphate-buffered saline for 2 or 4 weeks. The right Achilles tendons were used as controls. After 2 or 4 weeks, stress-shielded tendons appeared less smooth than control tendons, and the stress-shielded tendons formed adhesions with surrounding tissues. Transmission electron microscopy also showed disarray of the collagen fibrils and a significant increase in the number of small-diameter collagen fibrils. These changes were associated with increased expression of TNF-α, matrix metalloproteinase (MMP)-13, MMP-3, collagen I, and collagen III. Treatment with 2 weeks of etanercept injection reduced morphologic changes in collagen organization and structure induced by stress shielding. Etanercept treatment also attenuated upregulation of MMP-13, MMP-3, and collagen III levels. However, no significant difference was observed between the etanercept group and the phosphate-buffered saline group after 4 weeks of treatment. The current findings show that TNF-α inhibition can protect against the early stages of tendon tissue remodeling induced by stress shielding, but additional interventions may be necessary to prevent tendon degeneration with long-term stress shielding. [Orthopedics. 2017; 40(1):49-55.].
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16
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Rowson D, Knight MM, Screen HR. Zonal variation in primary cilia elongation correlates with localized biomechanical degradation in stress deprived tendon. J Orthop Res 2016; 34:2146-2153. [PMID: 26969839 PMCID: PMC5216897 DOI: 10.1002/jor.23229] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Accepted: 03/06/2016] [Indexed: 02/04/2023]
Abstract
Tenocytes express primary cilia, which elongate when tendon is maintained in the absence of biomechanical load. Previous work indicates differences in the morphology and metabolism of the tenocytes in the tendon fascicular matrix (FM) and the inter-fascicular matrix (IFM). This study tests the hypothesis that primary cilia in these two regions respond differently to stress deprivation and that this is associated with differences in the biomechanical degradation of the extracellular matrix. Rat tail tendon fascicles were examined over a 7-day period of either stress deprivation or static load. Seven days of stress deprivation induced cilia elongation in both regions. However, elongation was greater in the IFM compared to the FM. Stress deprivation also induced a loss of biomechanical integrity, primarily in the IFM. Static loading reduced both the biomechanical degradation and cilia elongation. The different responses to stress deprivation in the two tendon regions are likely to be important for the aetiology of tendinopathy. Furthermore, these data suggest that primary cilia elongate in response to biomechanical degradation rather than simply the removal of load. This response to degradation is likely to have important consequences for cilia signalling in tendon and as well as in other connective tissues. © 2016 The Authors. Journal of Orthopaedic Research Published by Wiley Periodicals, Inc. on behalf of Orthopaedic Research Society. J Orthop Res 34:2146-2153, 2016.
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Affiliation(s)
- Daniel Rowson
- Institute of Bioengineering and School of Engineering and Materials ScienceQueen Mary University of LondonMile End RoadLondonE1 4NSUnited Kingdom
| | - Martin M. Knight
- Institute of Bioengineering and School of Engineering and Materials ScienceQueen Mary University of LondonMile End RoadLondonE1 4NSUnited Kingdom
| | - Hazel R.C. Screen
- Institute of Bioengineering and School of Engineering and Materials ScienceQueen Mary University of LondonMile End RoadLondonE1 4NSUnited Kingdom
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17
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Abstract
Synopsis Tendinopathy is a very common disorder in both recreational and elite athletes. Many individuals have recurrent symptoms that lead to chronic conditions and termination of sports activity. Exercise has become a popular and somewhat efficacious treatment regime, and isolated eccentric exercise has been particularly promoted. In this clinical commentary, we review the relevant evidence for different exercise regimes in tendinopathy rehabilitation, with particular focus on the applied loads that are experienced by the tendon and how the exercise regime may affect these applied loads. There is no convincing clinical evidence to demonstrate that isolated eccentric loading exercise improves clinical outcomes more than other loading therapies. However, the great variation and sometimes insufficient reporting of the details of treatment protocols may hamper the interpretation of what may be the optimal exercise regime with respect to parameters such as load magnitude, speed of movement, and recovery period between exercise sessions. Future studies should control for these loading parameters, evaluate various exercise dosages, and think beyond isolated eccentric exercises to arrive at firm recommendations regarding rehabilitation of individuals with tendinopathies. J Orthop Sports Phys Ther 2015;45(11):853-863. Epub 14 Oct 2015. doi:10.2519/jospt.2015.5910.
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18
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Yang TH, Thoreson AR, An KN, Zhao C, Conover CA, Amadio PC. PAPP-A affects tendon structure and mechanical properties. J Struct Biol 2015; 192:59-66. [PMID: 26306763 DOI: 10.1016/j.jsb.2015.08.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Revised: 08/20/2015] [Accepted: 08/22/2015] [Indexed: 11/19/2022]
Abstract
Pregnancy-associated plasma protein-A (PAPP-A) serves to increase local insulin-like growth factor (IGF) stimulation of proliferation and differentiation in many tissues through proteolysis of inhibitory IGF-binding proteins. The purpose of this study was to investigate the effects of PAPP-A on tendon structure and mechanical properties. A total of 30 tails from 6-month-old mice were tested with 10 tails in each of following groups: PAPP-A knockout (KO), skeletal-specific PAPP-A overexpressing transgenic (Tg) and wild type (WT). Morphologically, the total tail cross-sectional area (CSA), individual tissue CSAs of bone, muscle and tendon, and fascicle diameter were measured. A fascicle pullout test was performed to assess stiffness and strength of interfascicular structures. Fascicles were mechanically characterized through low and high displacement rate uniaxial tension tests providing modulus at each rate, hysteresis area and stress relaxation ratio. The KO mice had a smaller total tail CSA (p<0.05), fascicle diameter (p<0.05), absolute tendon CSA (p<0.05), fast and slow stiffness (p<0.05 for both) and larger hysteresis area (p<0.05) compared to WT and Tg mice. On the other hand, the Tg mice had a larger fascicle diameter (p<0.05), absolute tendon CSA (p<0.05), higher interfascicular strength and stiffness (p<0.05) and lower fascicular modulus at low displacement rates (p<0.05) compared to WT and KO mice. Tg mice also had larger total tail CSA area (p<0.05) and smaller hysteresis area (p<0.05) than KO mice, and larger normalized tendon CSA (p<0.05) than WT mice. Based on these data, we conclude that PAPP-A affects fascicle structure, thereby affecting tendon phenotype.
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Affiliation(s)
- Tai-Hua Yang
- Biomechanics Laboratory and Tendon and Soft Tissue Biology Laboratory, Division of Orthopedic Research, Mayo Clinic, Rochester, MN 55905, USA
| | - Andrew R Thoreson
- Biomechanics Laboratory and Tendon and Soft Tissue Biology Laboratory, Division of Orthopedic Research, Mayo Clinic, Rochester, MN 55905, USA
| | - Kai-Nan An
- Biomechanics Laboratory and Tendon and Soft Tissue Biology Laboratory, Division of Orthopedic Research, Mayo Clinic, Rochester, MN 55905, USA
| | - Chunfeng Zhao
- Biomechanics Laboratory and Tendon and Soft Tissue Biology Laboratory, Division of Orthopedic Research, Mayo Clinic, Rochester, MN 55905, USA
| | - Cheryl A Conover
- Division of Endocrinology, Metabolism, and Nutrition, Endocrine Research Unit, Mayo Clinic College of Medicine, Rochester, MN 55905, USA.
| | - Peter C Amadio
- Biomechanics Laboratory and Tendon and Soft Tissue Biology Laboratory, Division of Orthopedic Research, Mayo Clinic, Rochester, MN 55905, USA.
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19
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Rossetto NP, Fabbro IMD, Piedade SR. How does static stretching influence the tendons mechanical response? ACTA ORTOPEDICA BRASILEIRA 2014; 21:258-61. [PMID: 24453678 PMCID: PMC3874994 DOI: 10.1590/s1413-78522013000500003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Accepted: 05/14/2013] [Indexed: 11/22/2022]
Abstract
OBJECTIVE Analyze in vitro the mechanical response of bovine calcaneus tendons subjected to static stretching in three different intervals (15, 30, 45 s). METHODS Six groups of bovine calcaneus tendons (n=10) were formed according to the static stretching protocol: three different intervals (15, 30, 45 s) and initial stretching percentage (2.5% and 3.5%). The control group (n=10) did not perform prior stretching. At the end of the stretching tests, the specimens were subjected to stress rupture tests. RESULTS The values for force relaxation presented stability after the 30(th) second (p<0.0001) at both levels of deformation. Greater force relaxation (p<0.0026) and the least tensile strength (p=0.0123) was observed in the group that was subjected to the highest stretch percentage (3.5%). No difference was observed between the rupture parameters of the stretch and control groups. The variables, stretch duration and percentage did not demonstrate interaction. CONCLUSION In relation to force relaxation, the 30 second interval seems to be the most effective when stretching tendons. This fact should be considered when establishing new clinical stretching protocols. Laboratory investigation.
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20
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Massoud EIE. Healing of subcutaneous tendons: Influence of the mechanical environment at the suture line on the healing process. World J Orthop 2013; 4:229-240. [PMID: 24147258 PMCID: PMC3801242 DOI: 10.5312/wjo.v4.i4.229] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Accepted: 08/29/2013] [Indexed: 02/06/2023] Open
Abstract
Tendon ruptures remain a significant musculoskeletal injury. Despite advances in surgical techniques and procedures, traditional repair techniques maintain a high incidence of rerupture or tendon elongation. Mechanical loading and biochemical signaling both control tissue healing. This has led some researchers to consider using a technique based on tension regulation at the suture line for obtaining good healing. However, it is unknown how they interact and to what extent mechanics control biochemistry. This review will open the way for understanding the interplay between mechanical loading and the process of tendon healing.
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21
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Effects of 40min of maintained stretch on the soleus and plantaris muscles of rats applied for different periods of time after hindlimb immobilization. Acta Histochem 2013; 115:505-11. [PMID: 23287280 DOI: 10.1016/j.acthis.2012.11.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2012] [Revised: 11/20/2012] [Accepted: 11/21/2012] [Indexed: 11/21/2022]
Abstract
Stretching is frequently used in physiotherapy to minimize or even reverse the alterations that occur after muscle disuse. Alterations that occur after 10 and 21 days of maintained stretch in soleus and plantaris muscles post-disuse were evaluated in the present study in experimental rats. Thirty adult female Wistar rats were divided into seven groups: hindlimb immobilization for 10 days; immobilization and 10 days stretched; immobilized and 21 days stretched; three control groups consisting of animals of different ages and anesthetized group. The right hindlimb was immobilized using a lightweight apparatus composed of two sections: (i) upper part: a small cotton T-shirt and, and (ii) lower part: a steel mesh to fix the ankle in plantar-flexion-shortened position. Fragments of the soleus and plantaris muscle were frozen and processed using histochemical and immunohistochemical methods. Limb immobilization caused important morphological alterations in skeletal muscle including: reduction in the number of type I fibers and an increase in type IIC fibers, reduction in the lesser diameter of type I, IIA and IIAD fibers and in the number of capillaries in soleus muscle. The stretching program applied for 10 days was insufficient to allow recovery from the disuse alterations in both muscles. However, after 21 days there were improved morphological characteristics, size and distribution of the different fibers.
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22
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Affiliation(s)
- Pramod B. Voleti
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6081;
| | - Mark R. Buckley
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6081;
| | - Louis J. Soslowsky
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6081;
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23
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Ma Y, Yan X, Zhao H, Wang W. Effects of interleukin-1 receptor antagonist on collagen and matrix metalloproteinases in stress-shielded achilles tendons of rats. Orthopedics 2012; 35:e1238-44. [PMID: 22868612 DOI: 10.3928/01477447-20120725-26] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Based on previous studies showing that interleukin-1 (IL-1) significantly increased after stress shielding, this article reports further research into the possible therapeutic applications of IL-1 receptor antagonist (IL-1Ra). Forty rats whose left Achilles tendons were denervated and completely stress shielded were divided into 5 groups: 2-week phosphate-buffered saline (PBS); 4-week PBS; 2-week IL-1Ra; 4-week IL-1Ra; and normal control. The Achilles tendons were tested morphologically, and the changes in collagen I and III, matrix metalloproteinases (MMP)-1 and -3, and tissue inhibitors of metalloproteinase (TIMP)-1 were determined. The collagen fibrils in the IL-1Ra groups were morphologically more similar to those in the control group than to those in the PBS groups. The collagen I levels increased in the 2-week groups. Significant differences existed between the PBS and IL-1Ra groups at 4 weeks. The MMP-1 level increased dramatically after stress shielding and increased less in the 2-week IL-1Ra group than in the 2-week PBS group. The degree of decrease of MMP-3 in the IL-1Ra groups was significantly less than that in the PBS groups. The collagen III and TIMP-1 levels continued to increase, and no difference was found between the PBS and IL-1Ra groups. Interleukin-1 receptor antagonist prevented morphological deterioration and collagen metabolism of the denervated Achilles tendons after stress shielding, likely by inhibiting the decline of MMP-3 and increasing MMP-1 levels at an early stage.
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Affiliation(s)
- Yanhong Ma
- Department of Rehabilitation Medicine, the Affiliated Sixth People’s Hospital of Shanghai Jiaotong University, Shanghai, China.
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24
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Kinneberg KRC, Galloway MT, Butler DL, Shearn JT. Effect of implanting a soft tissue autograft in a central-third patellar tendon defect: biomechanical and histological comparisons. J Biomech Eng 2012; 133:091002. [PMID: 22010737 DOI: 10.1115/1.4004948] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Previous studies by our laboratory have demonstrated that implanting a stiffer tissue engineered construct at surgery is positively correlated with repair tissue stiffness at 12 weeks. The objective of this study was to test this correlation by implanting a construct that matches normal tissue biomechanical properties. To do this, we utilized a soft tissue patellar tendon autograft to repair a central-third patellar tendon defect. Patellar tendon autograft repairs were contrasted against an unfilled defect repaired by natural healing (NH). We hypothesized that after 12 weeks, patellar tendon autograft repairs would have biomechanical properties superior to NH. Bilateral defects were established in the central-third patellar tendon of skeletally mature (one year old), female New Zealand White rabbits (n = 10). In one limb, the excised tissue, the patellar tendon autograft, was sutured into the defect site. In the contralateral limb, the defect was left empty (natural healing). After 12 weeks of recovery, the animals were euthanized and their limbs were dedicated to biomechanical (n = 7) or histological (n = 3) evaluations. Only stiffness was improved by treatment with patellar tendon autograft relative to natural healing (p = 0.009). Additionally, neither the patellar tendon autograft nor natural healing repairs regenerated a normal zonal insertion site between the tendon and bone. Immunohistochemical staining for collagen type II demonstrated that fibrocartilage-like tissue was regenerated at the tendon-bone interface for both repairs. However, the tissue was disorganized. Insufficient tissue integration at the tendon-to-bone junction led to repair tissue failure at the insertion site during testing. It is important to re-establish the tendon-to-bone insertion site because it provides joint stability and enables force transmission from muscle to tendon and subsequent loading of the tendon. Without loading, tendon mechanical properties deteriorate. Future studies by our laboratory will investigate potential strategies to improve patellar tendon autograft integration into bone using this model.
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Affiliation(s)
- Kirsten R C Kinneberg
- University of Cincinnati, School of Energy, Environmental, Biological and Medical Engineering, Biomedical Engineering Program, 601 Engineering Research Center, Cincinnati, OH 45220, USA.
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Svensson RB, Hansen P, Hassenkam T, Haraldsson BT, Aagaard P, Kovanen V, Krogsgaard M, Kjaer M, Magnusson SP. Mechanical properties of human patellar tendon at the hierarchical levels of tendon and fibril. J Appl Physiol (1985) 2012; 112:419-26. [DOI: 10.1152/japplphysiol.01172.2011] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Tendons are strong hierarchical structures, but how tensile forces are transmitted between different levels remains incompletely understood. Collagen fibrils are thought to be primary determinants of whole tendon properties, and therefore we hypothesized that the whole human patellar tendon and its distinct collagen fibrils would display similar mechanical properties. Human patellar tendons ( n = 5) were mechanically tested in vivo by ultrasonography. Biopsies were obtained from each tendon, and individual collagen fibrils were dissected and tested mechanically by atomic force microscopy. The Young's modulus was 2.0 ± 0.5 GPa, and the toe region reached 3.3 ± 1.9% strain in whole patellar tendons. Based on dry cross-sectional area, the Young's modulus of isolated collagen fibrils was 2.8 ± 0.3 GPa, and the toe region reached 0.86 ± 0.08% strain. The measured fibril modulus was insufficient to account for the modulus of the tendon in vivo when fibril content in the tendon was accounted for. Thus, our original hypothesis was not supported, although the in vitro fibril modulus corresponded well with reported in vitro tendon values. This correspondence together with the fibril modulus not being greater than that of tendon supports that fibrillar rather than interfibrillar properties govern the subfailure tendon response, making the fibrillar level a meaningful target of intervention. The lower modulus found in vitro suggests a possible adverse effect of removing the tissue from its natural environment. In addition to the primary work comparing the two hierarchical levels, we also verified the existence of viscoelastic behavior in isolated human collagen fibrils.
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Affiliation(s)
- René B. Svensson
- Faculty of Health Sciences, Institute of Sports Medicine Copenhagen, Bispebjerg Hospital & Center for Healthy Aging, University of Copenhagen, Copenhagen
- Nano-Science Center, University of Copenhagen, Copenhagen
| | - Philip Hansen
- Faculty of Health Sciences, Institute of Sports Medicine Copenhagen, Bispebjerg Hospital & Center for Healthy Aging, University of Copenhagen, Copenhagen
| | - Tue Hassenkam
- Nano-Science Center, University of Copenhagen, Copenhagen
| | - Bjarki T. Haraldsson
- Faculty of Health Sciences, Institute of Sports Medicine Copenhagen, Bispebjerg Hospital & Center for Healthy Aging, University of Copenhagen, Copenhagen
| | - Per Aagaard
- Institute of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense
| | - Vuokko Kovanen
- Biochemistry Laboratory, Department of Health Sciences, University of Jyväskylä, Jyväskylä, Finland
| | - Michael Krogsgaard
- Department of Orthopedic Surgery, Bispebjerg Hospital, Copenhagen, Denmark; and
| | - Michael Kjaer
- Faculty of Health Sciences, Institute of Sports Medicine Copenhagen, Bispebjerg Hospital & Center for Healthy Aging, University of Copenhagen, Copenhagen
| | - S. Peter Magnusson
- Faculty of Health Sciences, Institute of Sports Medicine Copenhagen, Bispebjerg Hospital & Center for Healthy Aging, University of Copenhagen, Copenhagen
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LIU MEIJUNJOLENE, CHOU SIAWMENG, GOH KHENGLIM, TAN SOONHUAT. CROSS-SECTIONAL AREA MEASUREMENT OF SOFT TISSUES IN VITRO: A NON-CONTACT LASER SCAN METHOD. J MECH MED BIOL 2011. [DOI: 10.1142/s0219519408002711] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Measurements of cross-sectional areas (CSAs) of soft tissues such as tendons and ligaments allow for the evaluation of the biomechanical properties of the tissue. Underlying in vitro techniques are data reduction approaches for determining the average thickness of the tissue and the assumption of the geometry of the cross-section, i.e. circular or elliptical. However, tissue distortions, sagging, and concavities could affect the reliability of these techniques, since these features may not be accounted for adequately. To address some of the concerns faced by these techniques, a non-contact (non-destructive) laser scan technique has been developed. In this technique, a laser scans along the axis of the tissue, a coordinate measuring machine simultaneously locates the corresponding point on the tissue based on the detection of reflected (attenuated) intensity, and, finally, computerized image analysis reconstructs the morphology of the tissue. This technique was applied to patellar tendons (PTs) from New Zealand rabbits. The scanning time for each PT was less than 2 minutes. Reconstructed three-dimensional surface plots revealed microconcavities consistent with images seen under optical microscopy. CSAs of these PTs were determined for repeatability and precision; results from a conventional approach which estimated the corresponding CSAs based on the average thickness and the assumption of ellipsoidal cross-sectional geometry were also determined for the purpose of comparison. Based on the standard cuboid model, the error between the laser technique and the conventional approach was within 0.4%; the reproducibility of the laser technique was within 2%.
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Affiliation(s)
- MEI JUN JOLENE LIU
- Division of Engineering Mechanics, School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
| | - SIAW MENG CHOU
- Division of Engineering Mechanics, School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
| | - KHENG LIM GOH
- Division of Engineering Mechanics, School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
| | - SOON HUAT TAN
- Division of Engineering Mechanics, School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
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Equinus deformity during tibial lengthening with ankle orthoses for equalization of leg-length discrepancies. J Orthop Sci 2011; 16:756-9. [PMID: 21842203 DOI: 10.1007/s00776-011-0139-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2011] [Accepted: 07/20/2011] [Indexed: 10/17/2022]
Abstract
BACKGROUND Although it is known that equinus deformity develops at a high rate during tibial lengthening, the efficacy of ankle orthoses for preventing equinus deformity and the etiology of equinus deformity remain unknown. The purpose of this study was to clarify the incidence and causes of equinus deformity in tibial lengthening with ankle orthoses worn for 16 h a day. METHODS 102 patients who had tibial lengthening were included in this study. There were 80 males and 22 females with ages at surgery from 6 to 70 years. Tibial lengthening was performed at the proximal tibia using an Ilizarov fixator. During limb lengthening, an ankle orthosis was used for more than 16 h a day to prevent equinus deformity. The rates and the causes of equinus deformity were investigated. RESULTS Equinus deformity was observed for eight cases (7.8%). Among these, the final gain in length was less than 5 cm in 6 patients. There were no significant differences between final gain in length, average lengthening rate, and final percentage gain of tibial length in the group with occurrence of equinus deformity and that without. CONCLUSIONS The incidence of equinus deformity was 7.8% during tibial lengthening wearing ankle orthoses.
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Reuvers J, Thoreson AR, Zhao C, Zhang L, Jay GD, An KN, Warman ML, Amadio PC. The mechanical properties of tail tendon fascicles from lubricin knockout, wild type and heterozygous mice. J Struct Biol 2011; 176:41-5. [PMID: 21821131 DOI: 10.1016/j.jsb.2011.07.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2011] [Revised: 07/20/2011] [Accepted: 07/24/2011] [Indexed: 11/18/2022]
Abstract
The purpose of this study was to analyze the effects of lubricin on tendon stiffness and viscoelasticity. A total of 36 mice were tested with 12 mice in each of the following groups: lubricin knock-out ⁻/⁻, heterozygous ⁺/⁻ and wild-type ⁺/⁺. A ramp test was used to determine the elastic modulus by pulling the fascicles to 2.5% strain amplitude at a rate of 0.05 mm/s. Then, followed by a relaxation test that pulled the fascicles to 5% strain amplitude at a rate of 2 mm/s. The fascicles were allowed to relax for 2 min at the maximum strain and a single-cycle relaxation ratio was used to characterize viscoelastic properties. There was no significant difference in the Young's modulus between the three groups (p > 0.05), but the knockout mice had a significantly (p < 0.05) lower relaxation ratio than the wild type mice. Based on these data, we concluded that lubricin expression has an effect on the viscoelastic properties of tendon fascicles. The clinical significance of this finding, if any, remains to be demonstrated.
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Affiliation(s)
- John Reuvers
- Biomechanics Laboratory, Division of Orthopedic Research, Mayo Clinic, Rochester, MN, USA
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The effect of muscle paralysis using Botox on the healing of tendon to bone in a rat model. J Shoulder Elbow Surg 2011; 20:688-97. [PMID: 21194973 DOI: 10.1016/j.jse.2010.09.016] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2010] [Revised: 08/30/2010] [Accepted: 09/30/2010] [Indexed: 02/01/2023]
Abstract
HYPOTHESIS Despite good clinical results after rotator cuff repair, follow-up studies show significant rates of failed healing. This may be because of excessive tension on the repaired tendon due to shoulder motion. We hypothesized that botulinum toxin A injections would result in improved attachment strength and collagen organization at the tendon-bone interface at early time points but may result in decreased mechanical properties at later time points because of the negative effects of stress deprivation. MATERIALS AND METHODS We performed division and repair of the supraspinatus tendon in 132 rats: 66 underwent repair alone and 66 received injections of botulinum toxin into the muscle before repair. Rats were killed at 4, 8, and 24 weeks and were evaluated by use of histologic, biomechanical, and micro-computed tomography analyses. RESULTS At 4 and 24 weeks, there was no significant difference in load to failure between groups. At 8 weeks, the botulinum group had a significantly lower load to failure compared with controls (27.7 N vs 46.7 N, P < .01). The weight of the supraspinatus muscle was significantly decreased at 4 and 8 weeks in the botulinum group, but it recovered by 24 weeks. Micro-computed tomography analysis showed the botulinum group to have significantly less bone volume, total mineral content, and total mineral density at 8 weeks. Histologic analysis showed formation of a more normal tidemark and increased collagen fiber organization in the botulinum specimens at 4 weeks. DISCUSSION Botulinum toxin A-treated specimens had increased collagen fiber organization at 4 weeks and decreased mechanical properties at later time points. The rapid healing of the rat rotator cuff likely makes it difficult to realize benefits from reduction in strain.
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Wang W, Tang X, Zhang J, Yan X, Ma Y. Complete stress shielding of the Achilles tendon: ultrastructure and level of interleukin-1 and TGF-β. Orthopedics 2010; 33:810. [PMID: 21053877 DOI: 10.3928/01477447-20100924-26] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Few studies emphasize the collagen metabolism-related cytokines and ultrastructure of the completely stress-shielded Achilles tendon. In this study, we used a rat model with complete stress shielding of the Achilles tendon to observe the changes in the ultrastructure of the Achilles tendon and concentration of IL-1 and TGF-β 3 weeks after stress shielding. The model group comprised 12 male Sprague-Dawley rats. The stress of the Achilles tendon of the left hind limb was shielded through tendon cerclage combined with sciatic nerve transection, and the right served as a normal control. Three weeks later, the ultrastructure of the Achilles tendon was observed under electron microscopy and IL-1 and TGF-β levels were determined by enzyme-linked immunosorbent assay. Compared with the control side, collagen fibrils of the shielded Achilles tendons were irregularly arranged and loose. The number of small-diameter collagen fibrils increased significantly with the decrease of the average diameter of collagen fibrils. At the same time, IL-1 concentrations increased significantly in the model group as compared to that in the control group, but no significant difference was found in TGF-β levels. These results suggest that IL-1 may play an important role in the change of ultrastructure after stress shielding.
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Affiliation(s)
- Wei Wang
- Department of Rehabilitation Medicine, Affiliated Sixth People’s Hospital of Shanghai Jiaotong University, Shanghai, China
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31
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Abstract
This review examines the effects of short- and long-term static and cyclic mechanical loading on the mechanical properties of tendons. Tendons do not alter their mechanical properties after static and cycling loading that occurs during fatiguing contractions. Adaptations can occur after the application of long-term loading, but the strain magnitude must exceed a given threshold.
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32
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Ciarletta P, Ben Amar M. A finite dissipative theory of temporary interfibrillar bridges in the extracellular matrix of ligaments and tendons. J R Soc Interface 2008; 6:909-24. [PMID: 19106068 DOI: 10.1098/rsif.2008.0487] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The structural integrity and the biomechanical characteristics of ligaments and tendons result from the interactions between collagenous and non-collagenous proteins (e.g. proteoglycans, PGs) in the extracellular matrix. In this paper, a dissipative theory of temporary interfibrillar bridges in the anisotropic network of collagen type I, embedded in a ground substance, is derived. The glycosaminoglycan chains of decorin are assumed to mediate interactions between fibrils, behaving as viscous structures that transmit deformations outside the collagen molecules. This approach takes into account the dissipative effects of the unfolding preceding fibrillar elongation, together with the slippage of entire fibrils and the strain-rate-dependent damage evolution of the interfibrillar bridges. Thermodynamic consistency is used to derive the constitutive equations, and the transition state theory is applied to model the rearranging properties of the interfibrillar bridges. The constitutive theory is applied to reproduce the hysteretic spectrum of the tissues, demonstrating how PGs determine damage evolution, softening and non-recoverable strains in their cyclic mechanical response. The theoretical predictions are compared with the experimental response of ligaments and tendons from referenced studies. The relevance of the proposed model in mechanobiology research is discussed, together with several applications from medical practice to bioengineering science.
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Affiliation(s)
- P Ciarletta
- Laboratoire de Physique Statistique de l'Ecole Normale Supérieure, 24 rue Lhomond, Paris Cedex 05, France.
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34
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Heinemeier KM, Olesen JL, Haddad F, Schjerling P, Baldwin KM, Kjaer M. Effect of unloading followed by reloading on expression of collagen and related growth factors in rat tendon and muscle. J Appl Physiol (1985) 2008; 106:178-86. [PMID: 18988763 DOI: 10.1152/japplphysiol.91092.2008] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Tendon tissue and the extracellular matrix of skeletal muscle respond to mechanical loading by increased collagen expression and synthesis. This response is likely a secondary effect of a mechanically induced expression of growth factors, including transforming growth factor-beta1 (TGF-beta1) and insulin-like growth factor-I (IGF-I). It is not known whether unloading of tendon tissue can reduce the expression of collagen and collagen-inducing growth factors. Furthermore, the coordinated response of tendon and muscle tissue to disuse, followed by reloading, is unclear. Female Sprague-Dawley rats were subjected to hindlimb suspension (HS) for 7 or 14 days, followed by 2, 4, 8, or 16 days of reload (RL) (n = 8 in each group). Age-matched controls were included for day 0, day 14 HS, and day 16 RL (n = 8). mRNA expression levels for collagen I (COL1A1), collagen III (COL3A1), TGF-beta1, connective tissue growth factor (CTGF), myostatin, and IGF-I isoforms were measured by real-time RT-PCR in Achilles tendon and soleus muscle. The tendon mass was unchanged, while the muscle mass was reduced by 50% after HS (P < 0.05) and returned to control levels during RL. Collagen I and III, TGF-beta1, and CTGF mRNA levels were unaltered by HS, although collagen III tended to decrease in muscle at day 7 HS. IGF-I isoforms were significantly induced in tendon after 7 days of HS (P < 0.001), and mechanogrowth factor increased in muscle at day 14 HS (P < 0.05). Reload increased muscle collagen I and III mRNA (>10-fold) (P < 0.001) and growth factor expression (P < 0.05), while the tendon response was limited to a moderate induction of collagen expression (2-fold) (P < 0.05). Unloading of tendon and muscle tissue did not reduce expression of collagen and collagen-inducing growth factors, indicating that the response to unloading is not opposite that of loading. Furthermore, the tendon response was clearly different and less pronounced than the muscle tissue response.
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Affiliation(s)
- K M Heinemeier
- Institute of Sports Medicine, Bispebjerg Hospital, DK-2400 Copenhagen NV, Denmark.
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35
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Hayashi R, Kondo E, Tohyama H, Saito T, Yasuda K. In vivo local administration of osteogenic protein-1 increases structural properties of the overstretched anterior cruciate ligament with partial midsubstance laceration. ACTA ACUST UNITED AC 2008; 90:1392-400. [DOI: 10.1302/0301-620x.90b10.20924] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
We report the effects of local administration of osteogenic protein-1 on the biomechanical properties of the overstretched anterior cruciate ligament in an animal model. An injury in the anterior cruciate ligament was created in 45 rabbits. They were divided into three equal groups. In group 1, no treatment was applied, in group II, phosphate-buffered saline was applied around the injured ligament, and in group III, 12.5 μg of osteogenic protein-1 mixed with phosphate-buffered saline was applied around the injured ligament. A control group of 15 rabbits was assembled from randomly-selected injured knees from among the first three groups. Each rabbit was killed at 12 weeks. The maximum load and stiffness of the anterior cruciate ligament was found to be significantly greater in group III than either group 1 (p = 0.002, p = 0.014) or group II (p = 0.032, p = 0.025). The tensile strength and the tangent modulus of fascicles from the ligament were also significantly greater in group III than either group I (p = 0.002, p = 0.0174) or II (p = 0.005, p = 0.022). The application of osteogenic protein-1 enhanced the healing in the injured anterior cruciate ligament, but compared with the control group the treated ligament remained lengthened. The administration of osteogenic protein-1 may have a therapeutic role in treating the overstretched anterior cruciate ligament.
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Affiliation(s)
- R. Hayashi
- Department of Orthopaedic Surgery, Yokohama City University School of Medicine, Fukuura 3–9, Kanazawa-ku, Yokohama City, Kanagawa Prefecture, 236-0004, Japan
| | - E. Kondo
- Department of Sports Medicine and Joint Reconstruction Surgery, Hokkaido University School of Medicine, Kita-15 Nishi-7, Kita-ku, Sapporo, 060-8638, Japan
| | - H. Tohyama
- Department of Sports Medicine and Joint Reconstruction Surgery, Hokkaido University School of Medicine, Kita-15 Nishi-7, Kita-ku, Sapporo, 060-8638, Japan
| | - T. Saito
- Department of Orthopaedic Surgery, Yokohama City University School of Medicine, Fukuura 3–9, Kanazawa-ku, Yokohama City, Kanagawa Prefecture, 236-0004, Japan
| | - K. Yasuda
- Department of Sports Medicine and Joint Reconstruction Surgery, Hokkaido University School of Medicine, Kita-15 Nishi-7, Kita-ku, Sapporo, 060-8638, Japan
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Local administration of interleukin-1 receptor antagonist inhibits deterioration of mechanical properties of the stress-shielded patellar tendon. J Biomech 2007; 41:884-9. [PMID: 18062978 DOI: 10.1016/j.jbiomech.2007.10.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2007] [Revised: 10/23/2007] [Accepted: 10/29/2007] [Indexed: 12/24/2022]
Abstract
We previously found that interleukin (IL)-1beta is over-expressed in the fibroblasts of the stress-shielded patellar tendon using a stress-shielding model [Uchida, H., Tohyama, H., Nagashima, K., Ohba, Y., Matsumoto, H., Toyama, Y., Yasuda, K., 2005. Stress deprivation simultaneously induces over-expression of interleukin-1beta, tumor necrosis factor-alpha, and transforming growth factor-beta in fibroblasts and mechanical deterioration of the tissue in the patellar tendon. Journal of Biomechanics 38(4), 791-798.]. Therefore, IL-1beta may play a role in tendon deterioration in response to stress deprivation. This study was conducted to clarify the effects of local administration of interleukin-1 receptor antagonist (IL-1ra) on the mechanical properties of the stress-shielded patellar tendon as well as the tendon fascicles harvested from it. Twenty-six mature rabbits were equally divided into Groups IL-1ra and PBS after the right patellar tendon underwent the stress-shielding treatment, which completely released the patellar tendon from tension by stretching the flexible wire installed between the patella and the tibial tubercle. In Group IL-1ra, IL-1ra was injected between the patellar tendon and the infra-patellar fat pad. In Group PBS, phosphate-buffered saline was injected in the same manner as IL-1ra. All rabbits were evaluated at 3 weeks after the stress-shielding procedure. The tangent modulus and the tensile strength of the patellar tendons were significantly greater in Group IL-1ra than in Group PBS, while there was no significant difference in the strain at failure between Groups IL-1ra and PBS. Concerning the mechanical properties of the fascicles harvested from the patellar tendon, however, we could not detect any significant differences in the tangent modulus, tensile strength, or strain at failure between Groups IL-1ra and PBS. The present study suggested that IL-1 plays an important role in the deterioration of the mechanical properties of the patellar tendon in response to stress shielding and that IL-1 does not affect the fascicles themselves.
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Kongsgaard M, Reitelseder S, Pedersen TG, Holm L, Aagaard P, Kjaer M, Magnusson SP. Region specific patellar tendon hypertrophy in humans following resistance training. Acta Physiol (Oxf) 2007; 191:111-21. [PMID: 17524067 DOI: 10.1111/j.1748-1716.2007.01714.x] [Citation(s) in RCA: 263] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
AIM To examine if cross-sectional area (CSA) differs along the length of the human patellar tendon (PT), and if there is PT hypertrophy in response to resistance training. METHODS Twelve healthy young men underwent baseline and post-training assessments. Maximal isometric knee extension strength (MVC) was determined unilaterally in both legs. PT CSA was measured at the proximal-, mid- and distal PT level and quadriceps muscle CSA was measured at mid-thigh level using magnetic resonance imaging. Mechanical properties of the patellar tendons were determined using ultrasonography. Subsequently, subjects performed 12 weeks of heavy resistance knee extension training with one leg (Heavy-leg), and light resistance knee extension training with the other leg (Light-leg). RESULTS The MVC increased for heavy-leg (15 +/- 4%, P < 0.05), but not for light-leg (6 +/- 4%). Quadriceps CSA increased in heavy-legs (6 +/- 1%, P < 0.05) while unchanged in light-legs. Proximal PT CSA (104 +/- 4 mm(2)) was smaller than the mid-tendon CSA (118 +/- 3 mm(2)), which again was smaller than distal tendon CSA (127 +/- 2 mm(2), P < 0.05). Light-leg PT CSA increased by 7 +/- 3% (P < 0.05) at the proximal tendon level, but was otherwise unchanged. Heavy-leg PT CSA increased at the proximal and distal tendon levels by 6 +/- 3% and 4 +/- 2% respectively (P < 0.05), but was unchanged at the mid tendon level. PT stiffness increased in heavy-legs (P < 0.05) but was unchanged in light-legs. Modulus remained unchanged in both legs. CONCLUSIONS To our knowledge, this study is the first to report tendon hypertrophy following resistance training. Further, the data show that the human PT CSA varies along the length of the tendon.
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Affiliation(s)
- M Kongsgaard
- Institute of Sports Medicine Copenhagen, Bispebjerg Hospital, Copenhagen, Denmark.
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38
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Eliasson P, Fahlgren A, Pasternak B, Aspenberg P. Unloaded rat Achilles tendons continue to grow, but lose viscoelasticity. J Appl Physiol (1985) 2007; 103:459-63. [PMID: 17412787 DOI: 10.1152/japplphysiol.01333.2006] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Tendons can function as springs and thereby preserve energy during cyclic loading. They might also have damping properties, which, hypothetically, could reduce risk of microinjuries due to fatigue at sites of local stress concentration within the tendon. At mechanical testing, damping will appear as hysteresis. How is damping influenced by training or disuse? Does training decrease hysteresis, thereby making the tendon a better spring, or increase hysteresis and thus improve damping? Seventy-eight female 10-wk-old Sprague-Dawley rats were randomized to three groups. Two groups had botulinum toxin injected into the calf muscles to unload the left Achilles tendon through muscle paralysis. One of these groups was given doxycycline, as a systemic matrix metalloproteinase inhibitor. The third group served as loaded controls. The Achilles tendons were harvested after 1 or 6 wk for biomechanical testing. An increase with time was seen in tendon dry weight, wet weight, water content, transverse area, length, stiffness, force at failure, and energy uptake in all three groups ( P < 0.001 for each parameter). Disuse had no effect on these parameters. Creep was decreased with time in all groups. The only significant effect of disuse was on hysteresis ( P = 0.004) and creep ( P = 0.007), which both decreased with disuse compared with control, and on modulus, which was increased ( P = 0.008). Normalized glycosaminoglycan content was unaffected by time and disuse. No effect of doxycycline was observed. The results suggest that in growing animals, the tendons continue to grow regardless of mechanical loading history, whereas maintenance of damping properties requires mechanical stimulation.
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Affiliation(s)
- Pernilla Eliasson
- Division of Orthopaedics, Department of Neuroscience and Locomotion, Faculty of Health Sciences, Linköping University, Linköping, Sweden
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39
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Arampatzis A, Karamanidis K, Morey-Klapsing G, De Monte G, Stafilidis S. Mechanical properties of the triceps surae tendon and aponeurosis in relation to intensity of sport activity. J Biomech 2006; 40:1946-52. [PMID: 17101142 DOI: 10.1016/j.jbiomech.2006.09.005] [Citation(s) in RCA: 132] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2006] [Accepted: 09/08/2006] [Indexed: 11/29/2022]
Abstract
The purpose of the present study was to investigate whether the mechanical properties (i.e. force strain relationship) of the triceps surae tendon and aponeurosis relate to the performed sport activity in an intensity-dependent manner. This was done by comparing sprinters with endurance runners and subjects not active in sports. Sixty-six young male subjects (26+/-5 yr; 183+/-6 cm; 77.6+/-6.7 kg) participated in the study. Ten of these subjects were adults not active in sports, 28 were endurance runners and 28 sprinters. All subjects performed isometric maximal voluntary plantar flexion contractions (MVC) on a dynamometer. The distal aponeuroses of the gastrocnemius medialis (GM) was visualised by ultrasound during the MVC. The results showed that only the sprinters had higher normalised stiffness (relationship between tendon force and tendon strain) of the triceps surae tendon and aponeurosis and maximal calculated tendon forces than the endurance runners and the subjects not active in sports. Furthermore, including the data of all 66 examined participants tendon stiffness correlated significantly (r=0.817, P<0.001) with the maximal tendon force achieved during the MVC. It has been concluded that the mechanical properties of the triceps surae tendon and aponeurosis do not show a graded response to the intensity of the performed sport activity but rather remain at control level in a wide range of applied strains and that strain amplitude and/or frequency should exceed a given threshold in order to trigger additional adaptation effects. The results further indicate that subjects with higher muscle strength possibly increase the margin of tolerated mechanical loading of the tendon due to the greater stiffness of their triceps surae tendon and aponeurosis.
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Affiliation(s)
- Adamantios Arampatzis
- German Sport University of Cologne, Institute of Biomechanics and Orthopaedics, Carl-Diem-Weg 6, 50933 Cologne, Germany.
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40
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Bensamoun SF, Tsubone T, Subramaniam M, Hawse JR, Boumediene E, Spelsberg TC, An KN, Amadio PC. Age-dependent changes in the mechanical properties of tail tendons in TGF-β inducible early gene-1 knockout mice. J Appl Physiol (1985) 2006; 101:1419-24. [PMID: 16794021 DOI: 10.1152/japplphysiol.00800.2005] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The purpose of this study is to investigate age-dependent changes in the architecture and mechanical properties of tendon in TGF-β inducible early gene-1 (TIEG) knockout mice. Wild-type and TIEG knockout mice, aged 1, 2, and 15 mo, were used. The mechanical properties of tail tendons isolated from these mice were determined using uniaxial tensile ramp (0.05 mm/s) and relaxation (5 mm/s) tests, with a strain of 10%. Mechanical parameters (Young's modulus from the ramp test; fast and static stresses from the relaxation test) were measured and recorded. The structure of the tail tendon fascicle was characterized by transmission electron microscopy. The results of the mechanical testing revealed no significant difference between the knockout and wild-type groups at 1 or 15 mo of age. However, the fascicles of the knockout mice at 3 mo of age exhibited decreased fast and static stresses compared with those of the wild-type mice. Electron microscopy revealed an increase in fibril size in the knockout mouse tendons relative to wild-type controls at 1 and 3 mo of age. These data indicate an important role for TIEG in tendon microarchitecture and strength in adult mice.
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Affiliation(s)
- Sabine F Bensamoun
- Biomechanics Laboratory, Department of Orthopedics, Mayo Clinic Rochester, Rochester, Minnesota 55905, USA
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41
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Sergi PN, Carrozza MC, Dario P, Micera S. Biomechanical Characterization of Needle Piercing Into Peripheral Nervous Tissue. IEEE Trans Biomed Eng 2006; 53:2373-86. [PMID: 17073344 DOI: 10.1109/tbme.2006.879463] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Several neural interfaces have been developed to control neuroprostheses and hybrid bionic systems. Among them, intraneural electrodes are very promising because they represent an interesting trade-off between the needs for high selectivity and for reduced invasiveness. However, in most of the cases, no particular attention has been devoted so far to the design of these systems starting from the mechanical properties of the system to be interfaced. The aim of this paper was to study and characterize in a quantitative way the piercing of peripheral nervous tissue in order to gather useful information to design intraneural interfaces able to reduce (as much as possible) the damages provoked by this task. In particular, attention has been paid to determine the values of force and pressure to carry out the piercing task in different velocity conditions. From the experimental data it was possible to characterize indirectly the tissue sinking under the needle tip. For each experimental velocity (ranging from 1 to 2000 mm/min) a threshold, under which the tissue cannot be pierced, has been calculated. The force magnitude required for piercing was shown to be in the range 0.3-25 mN for the different velocities. Moreover, differences between piercing carried out at very low velocity (multi-piercing) and at low velocity (mono-piercing) have been characterized and correlated with the physical characteristics of the nervous tissue. Experimental data have been integrated with a theoretical analysis of the neural interfaces piercing structures. The problem of buckling, representing for these structures the main cause of tissue piercing impossibility, has been analyzed. The nonlinear theoretical model allows to compare different needle geometries and materials with regard to piercing possibility at different velocities. Moreover, an optimization of piercing elements geometry with regard to amount of used material and space has been provided.
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Virchenko O, Aspenberg P. How can one platelet injection after tendon injury lead to a stronger tendon after 4 weeks? Interplay between early regeneration and mechanical stimulation. Acta Orthop 2006; 77:806-12. [PMID: 17068715 DOI: 10.1080/17453670610013033] [Citation(s) in RCA: 225] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Mechanical stimulation improves the repair of ruptured tendons. Injection of a platelet concentrate (platelet-rich plasma, PRP) can also improve repair in several animal models. In a rat Achilles tendon transection model, 1 postoperative injection resulted in increased strength after 4 weeks. Considering the short half-lives of factors released by platelets, this very late effect calls for an explanation. METHODS We studied the effects of platelets on Achilles tendon regenerates in rats 3, 5 and 14 days after transection. The tendons were either unloaded by Botulinum toxin A (Botox) injections into the calf muscles, or mechanically stimulated in activity cages. No Botox injections and ordinary cages, respectively, served as controls. Repair was evaluated by tensile testing. RESULTS At 14 days, unloading (with Botox) abolished any effect of the platelets and reduced the mechanical properties of the repair tissue to less than half of normal. Thus, some mechanical stimulation is a prerequisite for the effect of platelets at 14 days. Without Botox, both activity and platelets increased repair independently of each other. However, at 3 and 5 days, platelets improved the mechanical properties in Botox-treated rats. INTERPRETATION Platelets influence only the early phases of regeneration, but this allows mechanical stimulation to start driving neo-tendon development at an earlier time point, which kept it constantly ahead of the controls.
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Affiliation(s)
- Olena Virchenko
- Orthopaedics and Sports Medicine, Department of Neuroscience and Locomotion, Linköping University, Linköping, SE-581 85, Sweden
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43
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Ciarletta P, Micera S, Accoto D, Dario P. A novel microstructural approach in tendon viscoelastic modelling at the fibrillar level. J Biomech 2005; 39:2034-42. [PMID: 16214153 DOI: 10.1016/j.jbiomech.2005.06.025] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2004] [Accepted: 06/10/2005] [Indexed: 02/06/2023]
Abstract
Novel applications in rehabilitation, surgery and tissue engineering require the knowledge of the mechanical behaviour of the tissues at microstructural level. The aim of this work is to investigate the viscoelastic properties of the tendon from the interaction of its biological constituents in the fibrillar network. Traction, relaxation and creep in-vitro tests have been performed on porcine flexor digital tendons. A viscoelastic constitutive equation at finite deformation is presented. The fibrillar deformation modes are described through a network of adaptive links between collagen type I and decorin. The theoretical predictions fit accurately the experimental data. The results of the model demonstrate the mechanical importance of glycosaminoglycan chains of decorin for the differential recruitment and the activation of fibrillar collagen.
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Affiliation(s)
- P Ciarletta
- CRIM Laboratory, Scuola Superiore di Studi Universitari e Perfezionamento Sant'Anna, Piazza Martiri della Libertà 33, Pisa, Italy.
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Dressler MR, Butler DL, Boivin GP. Age-related changes in the biomechanics of healing patellar tendon. J Biomech 2005; 39:2205-12. [PMID: 16120443 DOI: 10.1016/j.jbiomech.2005.07.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2005] [Accepted: 07/08/2005] [Indexed: 12/23/2022]
Abstract
By 2030, there will be 70 million people in the United States over the age of 65, and by 2050, 22% of the US population will be considered elderly. It is generally believed that injuries in the elderly heal slower and less completely than in adolescents or young adults. To evaluate aging effects on tissue repair a surgical injury was created in the middle third of one patellar tendon in 1- and 4-5-year-old New Zealand White rabbits. The biomechanical properties of the isolated repair tissues and contralateral normal tendon tissues were compared at 6, 12 and 26 weeks post-injury. We hypothesized that repair tissues would exhibit age-related reductions in biomechanical properties at all time intervals of healing, both based on raw data and when normalized to values from contralateral tendons. Repairs from both age groups were similar, with no significant increase in maximum stress, strain at maximum stress, or modulus between 6 and 12 weeks. At 26 weeks, the repairs in the 4-year-old rabbits had higher maximum stress values than repairs in the 1-year-old rabbits (p=0.03). There were no significant differences in the strain at maximum stress or modulus. When repair tissue properties were normalized to values in the contralateral normal tendon, the maximum stress of the patellar tendon repair tissue from the 4 year old was significantly greater than the corresponding value from the 1 year old at the 26 week time point (p=0.04). In conclusion, these findings do not support the presence of age-related declines in the biomechanics of healing tendon.
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Affiliation(s)
- M R Dressler
- Department of Engineering, Dordt College, Sioux Center, IA, USA
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Abstract
Tendon disorders can be debilitating for patients and are difficult to manage. Current management strategies offer symptomatic relief, but may not result in definitive disease resolution. Despite remodeling, the biochemical and mechanical properties of healed tendon tissue never match those of intact tendon. This article outlines the stages of tendon healing, and reviews the possible strategies for optimizing tendon healing and repair, such as cytokine therapy, gene therapy, and tissue engineering.
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Affiliation(s)
- Pankaj Sharma
- Department of Trauma and Orthopaedic Surgery, Highcroft, Romsey Road, Wessex Deanery, Winchester, SO22 5DH, UK
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Haraldsson BT, Aagaard P, Krogsgaard M, Alkjaer T, Kjaer M, Magnusson SP. Region-specific mechanical properties of the human patella tendon. J Appl Physiol (1985) 2005; 98:1006-12. [PMID: 15448120 DOI: 10.1152/japplphysiol.00482.2004] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The present study investigated the mechanical properties of tendon fascicles from the anterior and posterior human patellar tendon. Collagen fascicles from the anterior and posterior human patellar tendon in healthy young men (mean ± SD, 29.0 ± 4.6 yr, n = 6) were tested in a mechanical rig. A stereoscopic microscope equipped with a digital camera recorded elongation. The fascicles were preconditioned five cycles before the failure test based on pilot data on rat tendon fascicle. Human fascicle length increased with repeated cycles ( P < 0.05); cycle 5 differed from cycle 1 ( P < 0.05), but not cycles 2–4. Peak stress and yield stress were greater for anterior (76.0 ± 9.5 and 56.6 ± 10.4 MPa, respectively) than posterior fascicles (38.5 ± 3.9 and 31.6 ± 2.9 MPa, respectively), P < 0.05, while yield strain was similar (anterior 6.8 ± 1.0%, posterior 8.7 ± 1.4%). Tangent modulus was greater for the anterior (1,231 ± 188 MPa) than the posterior (583 ± 122 MPa) fascicles, P < 0.05. In conclusion, tendon fascicles from the anterior portion of the human patellar tendon in young men displayed considerably greater peak and yield stress and tangent modulus compared with the posterior portion of the tendon, indicating region-specific material properties.
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Affiliation(s)
- B T Haraldsson
- Institute Sports Medicine, Bispebjerg Hospital, Bispebjerg bakke 23, 2400 Copenhagen NV, Denmark.
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Maganaris CN, Reeves ND, Rittweger J, Sargeant AJ, Jones DA, Gerrits K, De Haan A. Adaptive response of human tendon to paralysis. Muscle Nerve 2005; 33:85-92. [PMID: 16216011 DOI: 10.1002/mus.20441] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
To gain insight into the adaptive response of human tendon to paralysis, we compared the mechanical properties of the in vivo patellar tendon in six men who were spinal cord-injured (SCI) and eight age-matched, able-bodied men. Measurements were taken by combining dynamometry, electrical stimulation, and ultrasonography. Tendon stiffness and Young's modulus, calculated from force-elongation and stress-strain curves, respectively, were lower by 77% (P < 0.01) and 59% (P < 0.05) in the SCI than able-bodied subjects. The cross-sectional area (CSA) of the tendon was 17% smaller (P < 0.05) in the SCI subjects, but there was no difference in tendon length between the two groups. Our results indicate that paralysis causes substantial deterioration of the structural and material properties of tendon. This needs to be taken into consideration in the design of electrical stimulation protocols for rehabilitation and experimental purposes, and when interpreting changes in the contractile speed of paralyzed muscle.
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Affiliation(s)
- Constantinos N Maganaris
- Institute for Biophysical and Clinical Research into Human Movement, Manchester Metropolitan University, Alsager ST7 2HL, United Kingdom.
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Yamamoto E, Iwanaga W, Miyazaki H, Hayashi K. Effects of static stress on the mechanical properties of cultured collagen fascicles from the rabbit patellar tendon. J Biomech Eng 2002; 124:85-93. [PMID: 11871609 DOI: 10.1115/1.1427924] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
In-vitro tissue culture experiments were performed to study the effects of static stress on the mechanical properties of collagen fascicles obtained from the rabbit patellar tendon. After collagen fascicles having the diameter of approximately 300 microm were cultured for 1 and 2 wk under static stress between 0 and 3 MPa, their mechanical properties and crimp morphology were determined using a micro-tensile tester and a light microscope, respectively. The tensile strength and tangent modulus of the fascicles were significantly decreased by culture under no load compared to control fascicles. A statistically significant correlation, which was described by a quadratic curve, was observed between applied stress and tensile strength. The maximum tensile strength (16.7 MPa) was obtained at the applied stress of 1.2 MPa; the strength was within a range of control values. There was a similar correlation between applied stress and tangent modulus, and the modulus was maintained at control level under 1.3 MPa stress. The stress of 1.2 to 1.3 MPa is equivalent to approximately 50 percent of the peak stress developed in the intact rabbit patellar tendon by running. Strain at failure of cultured collagen fascicles was negatively correlated with applied stress, and that at 1.2 to 1.3 MPa stress was almost the same as the control value. Crimp morphology in the fascicles cultured under about 1.2 MPa stress was similar to that in control fascicles. These results indicate that cultured collagen fascicles change the mechanical properties and structure in response to static tensile stress. In addition, their mechanical properties and structure are maintained at control level if the static stress of 50 percent of in-vivo peak stress is applied.
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Affiliation(s)
- Ei Yamamoto
- Department of Mechanical Engineering, School of Biology-Oriented Science and Technology, Kinki University, Wakayama, Japan.
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Yamamoto E, Hayashi K, Yamamoto N. Effects of stress shielding on the transverse mechanical properties of rabbit patellar tendons. J Biomech Eng 2000; 122:608-14. [PMID: 11192382 DOI: 10.1115/1.1319660] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
With the aim of studying mechanisms of the remodeling of tendons and ligaments, the effects of stress shielding on the rabbit patellar tendon were studied by performing tensile and stress relaxation tests in the transverse direction. The tangent modulus, tensile strength, and strain at failure of non-treated, control patellar tendons in the transverse direction were 1272 kPa, 370 kPa, and 40.5 percent, respectively, whereas those of the tendons stress-shielded for 1 week were 299 kPa, 108 kPa, and 40.4 percent, respectively. Stress shielding markedly decreased tangent modulus and tensile strength in the transverse direction, and the decreases were larger than those in the longitudinal direction, which were determined in our previous study. For example, tensile strength in the transverse and longitudinal direction decreased to 29 and 50 percent of each control value, respectively, after 1 week stress shielding. In addition, the stress relaxation in the transverse direction of stress-shielded patellar tendons was much larger than that of nontreated, control ones. In contrast to longitudinal tensile tests for the behavior of collagen, transverse tests reflect the contributions of ground substances such as proteoglycans and mechanical interactions between collagen fibers. Ground substances provide lubrication and spacing between fibers, and also confer viscoelastic properties. Therefore, the results obtained from the present study suggest that ground substance matrix, and interfiber and fiber-matrix interactions have important roles in the remodeling response of tendons to stress.
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Affiliation(s)
- E Yamamoto
- Laboratory on Mechanical Behavior of Materials, Department of Mechanical Engineering, School of Biology-Oriented Science and Technology, Kinki University, Naga, Wakayama 649-6493, Japan
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Yamamoto E, Tokura S, Yamamoto N, Hayashi K. Mechanical properties of collagen fascicles from in situ frozen and stress-shielded rabbit patellar tendons. Clin Biomech (Bristol, Avon) 2000; 15:284-91. [PMID: 10675670 DOI: 10.1016/s0268-0033(99)00072-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
OBJECTIVE To know the effects of stress shielding on the biomechanical properties of collagen fascicles obtained from in situ frozen patellar tendons (an autograft model). DESIGN Collagen fascicles of approximately 300 microm in diameter were obtained from in situ frozen rabbit patellar tendons and also from in situ frozen and stress-shielded ones, and their mechanical properties and fibroblast density were determined. BACKGROUND Stress shielding changes the mechanical properties of in situ frozen patellar tendons in which there exist no fibroblasts. The mechanisms of this phenomenon have not been studied well. METHOD Patellar tendons of both in situ frozen group and in situ frozen and stress-shielded group were frozen in situ by liquid nitrogen to kill fibroblasts. Then, in the in situ frozen and stress-shielded group, no tension was applied to the tendons for 2, 3, and 6 weeks, while normal tension was applied to the tendons of the in situ frozen group. Tensile properties of the collagen fascicles obtained from these tendons were determined using a microtensile tester, and were compared to the collagen fascicles from non-frozen, stress-shielded patellar tendons. RESULTS Tangent modulus and tensile strength of collagen fascicles from the in situ frozen and stress-shielded group progressively decreased with the time of stress shielding; however, these decreases were much smaller than those of the fascicles obtained from non-frozen, stress-shielded tendons. Although there were few fibroblasts in the patellar tendon of the in situ frozen and stress-shielded group at 2 weeks, the modulus and strength of the fascicles from the posterior portion were significantly lower than those in the in situ frozen group. In addition, the reduction of strength caused by stress shielding was much smaller in collagen fascicles than in bulk patellar tendons. CONCLUSION The mechanical properties of collagen fascicles in in situ frozen tendons (an autograft model) are affected by stress shielding even under acellular condition. RelevanceThe in situ frozen, stress-shielded patellar tendon is a model of augmented autografts which are clinically used for the reconstruction of injured anterior cruciate ligaments. The sub-macroscopic studies of the tendon are useful to understand the mechanisms of the reduction of graft strength and its gradual recovery observed after reconstruction.
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Affiliation(s)
- E Yamamoto
- Laboratory on Mechanical Behavior of Materials, Department of Mechanical Engineering, School of Biology Oriented Science and Technology, Kinki University, Naga, Wakayama, Japan
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