Protection of preconditioning, postconditioning and combined therapy against hepatic ischemia/reperfusion injury.

OBJECTIVE: To study the protective effect of ischemic preconditioning (I-pre) and ischemic postconditioning (I-post) against ischemia/reperfusion (I/R) injury in rat's liver. METHODS: Using rat model of hepatic segmental I/R injury, rats were divided into 5 groups: Group A (sham group), Group B (I/R injury), Group C (I-pre group), Group D (I-post group) and Group E (combined treatment of I-pre and I-post). Serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), malondialdehyde (MDA), glutathione (GSH), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and myeloperoxidase (MPO) in hepatic tissues were determined, respectively. In addition, 7 days'survival of Groups B, C, D and E were evaluated. RESULTS: Compared with Group B, Groups C, D and E exhibited significantly decreased ALT and AST release, minimized tissue injury, suppressed values of MDA and MPO, increased activities of SOD, GSH-Px and GSH (P less than 0.05), as well as improved animal survival. The differences among Groups C, D and E were not statistically significant. CONCLUSIONS: I-pre, I-post and combined therapy of I-pre and I-post have protective effect against hepatic I/R injury, which is correlated with its function of reducing the production of reactive oxygen species, maintaining the activities of antioxidant systems and suppressing neutrophils recruitment. No additive effect can be obtained in Group E.