The optimal time window of ischemic preconditioning (IPC) on the reperfusion injury in moderate to severe hepatocirrhosis in rats.

Purpose: To evaluate the effects of different-time ischemic preconditioning (IPC) schemes on the ischemia-reperfusion (I/R) injury in moderate to severe hepatocirrhosis in rats and to identify the optimal time window of IPC.

Methods: A total of 90 male SD rats with moderate to severe hepatocirrhosis were randomly divided into 5 groups (IR group, 5-10 min-IPC group, 8-10 min-IPC group, 10-10 min-IPC group and 15-10 min-IPC group), in which the liver was preconditioned by IPC of various durations, and then subjected to I/R injury in the last four groups. Thirty-six normal (non-cirrhotic) SD rats were divided into 2 groups (IR group and 10-10 min-IPC group). Ischemia-reperfusion injury was induced by clamping of the portal triad for 30 min followed by reperfusion for 30 min. Hepatocellular viability was assessed by measuring the concentration of ALT and AST in serum. The concentration of NO in serum and those of MDA, MPO, and SOD in the liver tissue were also assessed at 1h, 4h, and 24h after the operation respectively.

Results: After 30-30min of I/R, the levels of ALT and AST were significantly elevated in the IR group and the groups under IPC, but the elevations were significantly lower in the 5-10 min-IPC group and the 8-10 min-IPC group, especially at 4h after I/R (P<0.05). The levels of MDA and MPO in liver tissue were lower in the 5-10 min-IPC and 8-10min-IPC groups than in the rest of the IPC groups and IR group in the cirrhotic rats, and the level of SOD was higher (P <0.05). The level of serum NO was significantly higher in the 5-10 min-IPC and 8-10min-IPC groups than in the rest of the cirrhotic groups (P <0.05).

Conclusions: The 5-10 min through 8-10 min-IPC achieves the highest protective effect on the I/R injury of moderate to severe hepatocirrhosis. With the aggravation of liver cirrhosis, the pre-implementation time has been shortened. Thus, IPC of 5-10min may be effective for severe liver cirrhosis.