Extracellular vesicles derived from mesenchymal stem cells mediate extracellular matrix remodeling in osteoarthritis through the transport of microRNA-29a

Figure 1 Morphological observation of bone marrow-derived mesenchymal stem cells and identification of bone marrow-derived mesenchymal stem cells-exosomes. A: The bone marrow-derived mesenchymal stem cells (BMSCs) had a homogeneous spindle morphology; B: The BMSC-exosomes (Exos) were approximately 60–160 nm in diameter and had a sub-circular, typical teatoid appearance; C: The nanoparticle tracking analysis results showed that the concentration of BMSC-Exos was 3.43 × 10⁹/mL and their average particle size was 131.9 nm; D: The results of the western blotting assays showed that the expression of CD9, heat shock protein 70, and tumor necrosis factor-alpha-stimulated gene 101 was positive. Exo: Exosomes; HSP: Heat shock protein; TSG: Tumor necrosis factor-alpha-stimulated gene.

Figure 2  The results of nanoparticle tracking analysis of bone marrow-derived mesenchymal stem cells-miR-29a-Exos.

Figure 3 The results of the quantitative reverse transcription polymerase chain reaction assay. ^aP < 0.001. Exo: Exosomes.

Figure 4 Micro-computed tomography and three-dimensional reconstruction of the knee joint of rats. Micro-computed tomography images of the knee joint and the 3D reconstructed images of the corresponding specimens for each group of rats at four weeks and eight weeks are presented. Exo: Exosomes; NC: Negative control.

Figure 5 Photographs of gross specimens of rat knee joints. Exo: Exosomes; NC: Negative control.

Figure 6 Pelletier gross scores and the modified Mankin score. A: Pelletier gross scores; B: The modified Mankin score. ^bP < 0.01, ^cP < 0.05, ^dP < 0.01. Exo: Exosomes; NC: Negative control.

Figure 7 Images of the condyles of femur of rats stained with hematoxylin and eosin and Safranin O-fast green. A: Images of the condyles of femur of rats stained with hematoxylin and eosin. We have re-uploaded the images; all of them depict cross-sectional staining of the femoral condyle; B: Images of condyles of femur of rats stained with Safranin O-fast green. Exo: Exosomes; NC: Negative control.

Figure 8 The expression of type II collagen and proteoglycans. A: The expression of type II collagen; B: The expression of proteoglycans. Exo: Exosomes; NC: Negative control.