Objective:To investigate the protective effect of remifentanil preconditioning on liver ischemia and reperfusion injury in rats.Methods:Forty-eight healthy adult SD rats,weighing 200-300 g,were divided into 4 groups:ischemic reperfusion group(I/R),ischemic preconditioning group(IPC),sham operation group(Sham),and remifentanil preconditioning group(RPC).The RPC group was further subdivided into 3 subgroups according to the dose of remifentanil:0.2 μg·kg-1·min-1(RPC1 group),1 μg·kg-1·min-1(RPC2 group ),and 10 μg·kg-1·min-1(RPC3 group).All rats except for those in the sham group were subjected to ischemia for 45 min and followed by reperfusion for 2 hours.Serum levels of alanine aminotransferase(ALT),aspartate aminotransferase(AST) and liver homogenate levels of MDA,SOD were determined.H-E staining was used to observe the hepatic histopathological changes and TUNEL staining was used to examine hepatocyte apoptosis.Results:In I/R and RPC1 group,serum ALT and AST were significantly increased; hepatic homogenate MDA content was increased and SOD content was decreased,accompanied by aggravated pathological injury; TUNEL staining showed large amount of apoptotic cells.Compared with I/R and RPC1 groups,serum ALT and AST levels in IPC,RPC2,and RPC3 groups were significantly decreased after liver ischemia and reperfusion,accompanied by decreased homogenate MDA level,increased SOD level,and improved pathological injury.TUNEL staining showed much less apoptotic hepatocytes in IPC,RPC2,and RPC3 groups compared with I/R and RPC1 groups.No obvious changes in histopathology or in other parameters were observed in the sham group.Conclusion:Pre-treatment with remifentanil,like ischemic precondition,can protect liver from ischemia and reperfusion injury.