Effect of ischemic postconditioning on ischemia reperfusion injury of the remnant liver after major hepatectomy

Objective: To explore the effect of ischemic postconditioning on ischemia reperfusion injury of the remnant liver after major hepatectomy. Methods: One hundred and fifteen healthy male Sprague-Dawley rats of clean grade, weighing 230-280 g, were selected. Twenty-five of them were chosen to be assigned randomly into five groups: 70% simple hepatectomy group (PH1), 70% hepatectomy combined with ischemia reperfusion group (PHIR1), three cycles of 10 s-10 s ischemic postconditioning group (IPO1), three cycles of 30 s-30 s ischemic postconditioning group (IPO2) and three cycles of 60 s-60 s ischemic postconditioning group (IPO3). The inferior vena blood and the remnant liver tissues were harvested 6 h after reperfusion to be detected for serum ALT and AST activities and apoptosis index (AI) of hepatocytes to screen the optimal regimen with the best protection. The remaining 90 rats were randomly divided into three groups: PH2, PHIR2 and IPO groups. The inferior vena blood and the remnant liver tissues were harvested at 1, 6, 12, 24 and 48 h after reperfusion in each group, 6 rats at each time point. Serum ALT and AST activities and hepatic tissue levels of MDA, SOD and MPO were determined. Results: Compared with those in PH1 group, serum ALT, AST activities and hepatocyte AI in PHIR1, IPO1, IPO2 and IPO3 groups were all increased (P<0.05). Compared with those in PHIR1 group, serum ALT, AST activities and AI in IPO1, IPO2 and IPO3 groups were all decreased but had a significant difference only in IPO2 groups (P<0.05). The treatment of IPO2 was determined as the postconditioned regimen of the subsequent experiment. The latter results showed that serum ALT, AST activities as well as levels of MDA and MPO decreased but SOD increased at each time point in IPO group in comparison with PHIR2 group (P<0.05). Conclusion: Ischemic postconditioning can attenuate ischemia reperfusion injury of the remnant liver after major hepatectomy, and its mechanism is related to inhibiting oxidative stress as well as reducing production of free radicals and infiltration of inflammatory cells.