Published online Feb 7, 2017. doi: 10.3748/wjg.v23.i5.830
Peer-review started: September 26, 2016
First decision: December 2, 2016
Revised: December 8, 2016
Accepted: December 21, 2016
Article in press: December 21, 2016
Published online: February 7, 2017
Processing time: 118 Days and 19.6 Hours
To investigate the underlying mechanisms of the protective role of remote ischemic perconditioning (RIPerC) in rat liver transplantation.
Sprague-Dawley rats were subjected to sham, orthotopic liver transplantation (OLT), ischemic postconditioning (IPostC) or RIPerC. After 3 h reperfusion, blood samples were taken for measurement of alanine aminotransferase, aspartate aminotransferase, creatinine (Cr) and creatinine kinase-myocardial band (CK-MB). The liver lobes were harvested for the following measurements: reactive oxygen species (ROS), H2O2, mitochondrial membrane potential (ΔΨm) and total nitric oxide (NO). These measurements were determined using an ROS/H2O2, JC1 and Total NOx Assay Kit, respectively. Endothelial NO synthase (eNOS) was analyzed by reverse transcription-polymerase chain reaction (RT-PCR) and western blotting, and peroxynitrite was semi-quantified by western blotting of 3-nitrotyrosine.
Compared with the OLT group, the grafts subjected to RIPerC showed significantly improved liver and remote organ functions (P < 0.05). ROS (P < 0.001) including H2O2 (P < 0.05) were largely elevated in the OLT group as compared with the sham group, and RIPerC (P < 0.05) reversed this trend. The collapse of ΔΨm induced by OLT ischemia/reperfusion (I/R) injury was significantly attenuated in the RIPerC group (P < 0.001). A marked increase of NO content and phosphoserine eNOS, both in protein and mRNA levels, was observed in liver graft of the RIPerC group as compared with the OLT group (P < 0.05). I/R-induced 3-nitrotyrosine content was significantly reduced in the RIPerC group as compared with the OLT group (P < 0.05). There were no significant differences between the RIPerC and IPostC groups for all the results except Cr. The Cr level was lower in the RIPerC group than in the IPostC group (P < 0.01).
Liver graft protection by RIPerC is similar to or better than that of IPostC, and involves inhibition of oxidative stress and up-regulation of the PI3K/Akt/eNOS/NO pathway.
Core tip: This study is believed to be the first to investigate remote ischemic conditioning using a novel model of remote ischemic perconditioning (RIPerC) in liver transplantation and to identify the PI3K/Akt/endothelial nitric oxide (NO) synthase/NO axis involved. Compared to the traditional method of ischemic postconditioning, RIPerC works similar to or better than it and overcomes the main concern of increasing total ischemic time, which may lead to problems. RIPerC appears as the most promising technique to avoid ischemia/reperfusion injury in liver transplantation and is convenient clinically.