The Effect Of Piperine On Liver Ischemia-reperfusion Injury And Its Underlying Mechanism

Background: Hepatic ischemia reperfusion injury(HIRI)is a common complication after liver surgery,which is related to the high postoperative mortality.However,the treatment of hepatic ischemia reperfusion injury remains to been solved.It is reported that Piperine has the effect of anti-inflammatory and antioxidant,and has a significant protective effect on other liver injuries.Therefore,the purpose of this study was to investigate the effect of piperine on hepatic ischemia reperfusion injury and the potential molecular mechanism.Methods: C57/6J mice were randomly divided into Sham group(SHAM)and hepatic ischemia reperfusion group(HIR).The hepatic artery and portal vein of the left lobe and middle lobe of the liver of mice were clipped by non-invasive artery clip.The artery clip was removed after 90 minutes of ischemia and reperfusion was performed for 1 h,6 h,12 h,24 h and 48 h,respectively.The liver pathological sections were observed and the serum transaminase activity was measured to evaluate the degree of liver injury,and the optimal reperfusion time point was selected.Then mice were randomly divided into four groups: Sham operation group(Sham),hepatic ischemia reperfusion group(HIR),liver ischemia reperfusion + Piperine group(HIR+ PI),and Piperine control group(PI),with 6 mice in each group.After 24 h reperfusion,blood was collected and serum was separated to determine transaminase biological activity,then the mice were sacrificed and liver tissue was collected.Hematoxylin and eosin(H&E)staining were performed and the degree of liver tissue injury was evaluated.Oxidative stress in liver tissue was measured by dihydroergotamine(DHE).Apoptosis of hepatocytes was measured by terminal dexynucleotidyl transferase(Td T)-mediated d UTP nick end labeling(TUNEL).The expressions of TNF-α and IL-6 in liver tissue were detected by immunohistochemistry(IHC).Immunofluorescence(IF)was used to measure expressions of inflammatory cells in liver tissue.Western blot(WB)was used to measure the expressions of related proteins in liver tissue.Results: 1.Compared with the Sham group,there was apparent liver damage in HIRI group,and the liver injury degree increased with the prolongation of reperfusion time.Serum ALT and AST activities were significantly increased after the reperfusion of 1 h,6 h,12 h and 24 h.The difference was statistically significant(P<0.05).2.Compared with the Sham group,the activity of ALT and AST in HIR group was significantly increased.Apoptosis of hepatocyte apoptosis was found in HIR group.The content of ROS and infiltration of inflammatory cells increased.The expressions of IL-6,TNF-α,TLR4,p-IRAK-1,p-p65 and p-p-38 increased.The differences were statistically significant(P<0.05).Compared with the HIR group,the activity of ALT and AST in HIR+IP group was significantly decreased.Apoptosis of hepatocyte apoptosis,the content of ROS and infiltration of inflammatory cells decreased.And the expressions of IL-6,TNF-α,TLR4,p-IRAK-1,p-p65 and p-p-38 decreased.The differences were statistically significant(P<0.05).Conclusion: 1.Serum transaminase activity increased at 1 h of reperfusion and continued to 24 h.Liver injury would gradually worsen with the prolongation of reperfusion time.2.Piperine can alleviate hepatic ischemia-reperfusion injury through anti-inflammatory,anti-oxidative and anti-apoptotic effects,and this protective effect may be related to the inhibition of TLR4 signaling pathway.