The Protective Effect Of TAK242 On Hepatic Ischemia-Reperfusion Injury In Rat Livers From Donation After Cardiac Death

Background:Liver transplantation remains currently an effective treatment for patients with end-stage liver disease.Donation after brain death has been unable to meet the increasing demand for clinical requirements,and donation after circulatory death is an important channel to solve the shortage of organs.Ischemia reperfusion injury is the tissue damage caused when blood supply returns to tissue after a period of ischemia.IRI is an important risk factor for the nonfunction of graft and the acute and acute or chronic graft rejection after liver transplantation.Compared with the DBD graft,the DCD graft has a longer warm ischemia period and is more sensitive to IRI during the transplantation process.Objective:Aseptic inflammation during IRI is an important cause of tissue damage.High mobility group box 1(HMGB1)is a nuclear protein with important functions such as DNA repair,transcription and cell signal transduction.Binding with TLR4 can induce nonspecific immunity and participate in the pathogenesis of many diseases.Cheng.This study was designed to investigate the effect and mechanism of HMGB1/TLR4 on ischemia-reperfusion injury of DCD graft in rats.Methods:TLR4 specific inhibitor TAK242 was used.SD male rats were randomly divided into four groups: control group,TAK242 group,DCD group and DCD +TAK-242 group.Rats were pretreated with TAK242 or its vehicle,then livers harvested without warm ischemia or with warm ischemia.Livers were stored in cold University of Wisconsin solution for 24 h,and subsequently perfused for 60?min with an isolated perfused rat liver system.Hepatic injury was observed by HE staining and liver enzyme level.Hepatocyte apoptosis was detected by Tunel method,MDA and ROS levels were detected by Elisa,subcellular injury was observed by electron microscopy,HMGB1,TLR4 and downstream inflammatory factors were detected by fluorescence quantitative PCR and Western blot.Results:The liver tissue damage,liver enzyme level,apoptotic rate and the expression levels and protein levels of HMGB1,TLR4,IL-1beta,IL-6,TNF-alpha and COX2 of DCD group were significantly higher than those of control group.Blocking TLR4 pathway significantly reduced liver tissue damage,liver enzyme level,hepatocyte apoptosis rate,the expression and protein levels of TLR4 and downstream inflammatory factors IL-1beta,IL-6,TNF-alpha and COX2 in DCD liver,but had no significant effect on the expression of HMGB1 and protein levels in DCD liver.After blocking TLR4 pathway,liver tissue damage,liver enzyme level and hepatocyte apoptosis rate,HMGB1,TLR4,and downstream factors such as IL-1beta,IL-6,TNF-alpha,COX2 expression level and protein level in DCD were still higher than those in normal liver.Blocking TLR4 pathway had no significant effect on normal donor liver in rats.Conclusion:This study suggests that TLR4 signaling pathway plays an important role in IRI of DCD graft in rats.TAK-242 ameliorated IRI of DCD graft in rats by blocking TLR4 signaling pathway,which may provide potential benefit to liver transplantation.