Ischemic preconditioning attenuates ischemia-reperfusion injury of cirrhotic liver in rats.

Objective To investigate the protective effect of ischemic preconditioning by Pringle's maneuver against ischemia-reperfusion injury of cirrho-tic livers in rats and its mechanism.Methods Cirrhotic model were induced by subcutaneous injection of carbon tetrachloride(CCI4) in male Wistar rats.Rats were randomized into two groups: the control group rats underwent anesthesia and midline laparotomy only;the ischemic preconditioning(IP) group rats were preconditioned with short-term(15 minutes) hepatic ischemia.After a 48-hour recovery,all rats were exposed to a longer(30minutes) warm ischemia.Western blotting was used to test the expression of heat shock protein 70(HSP70) at 6,24,48 hours after IP.Serum ALT and AST levels and GSH levels in hepatic tissue were measured at 1,3 hours and 3 hours respectively after reperfusion.Histology of the liver after reperfusion was also compared.Results HSP70 expression was induced in IP group at greater intensity than that in control group 24 and 48 hours after IP.The survival rate in IP group(93.10%) was significantly higher than that in control group(73.33%,P0.05).The serum ALT and AST in group IP(481.86±253.79IU/L and 814.86±470.30IU/L,respectively) 3 hours after reperfusion were significantly lower than those in control group(1511±421.50IU/L and 2765.86±1004.37IU/L,respectively;P0.01);while GSH levels in hepatic tissue(549.08±40.80 mg/g protein) were significantly higher than those in control group(502.79±40.80mg/g protein,P0.05).Compared with control group,hepatic cell damage in IP group was significantly decreased.Conclusion These data indicate that IP can induce HSP70 expression at great intensity,which may increase GSH level or its activity in cirrhotic liver of the rats and protect against ischemia-reperfusion injury in the liver.