Objective: To investigate the protective effect of the first window (FW)of liver ischemic preconditioning(IPC), the second window(SW) of remote (leg) ischemic preconditioning(RPC) and conbined applications of liver and lges IPC to against liver ischemia/reperfusion(I/R) injury in the rat, and to investigate the mechanism of the protection.
Methods: Rats were randomly divided into five groups (n=8 each):(1) Sham group (S group), rats without IPC, (2) Rats with 5 min IPC (IPC group); (3) Rat wiht both liver and lower limbs IPC and repeated three times (RPC group); (4) IPC 24 h after RPC group; (5) IR without IP (I/R group)； except S group, the rats were subjected to 60 min sustained liver ischemia followed by 180 min reperfusion.All ischemia rats were only subjected to 70% liver ischemia. Finally，blood and liver samples were obtained to determine the activity of ALT and AST, the expressions of TNF-α and HSP70  protein,and liver wet/dry weight (W/D) and pathology.
Results: All IPC group and RPC group and IPC+RPC group had obviously lower levels of ALT, AST,  W/D, TNF-α than that of the I/R group (P＜0.01), but had obviously higher expressions of HSP70 protein than the I/R group (P＜0.01), howerer,all the indices between IPC group and RPC group and IPC+RPC group had no statistical  difference(P＞0.05).
Conclusions: The FW of the IPC, the SW of the RPC and combined applications can lessen hepatic I/R injury. There is no significant difference in the protective intensity of the 3 motheds. The protective effects possibly are due to suppression of TNF-α production, induction of protein HSP70 expression and improvement of liver microcirculation.