[Effects of ischemic postconditioning on the expression of heme oxygenase-1 in the liver graft with ischemia and reperfusion injury in rats].

OBJECTIVE: To investigate the effects of ischemic postconditioning on the expression of HO-1 in the liver graft ischemia and reperfusion injury in rats. METHODS: Fifty-six male SD rats were randomly divided into four groups: sham-operation group (sham) (n = 8), ischemia and reperfusion group (I/R)(n = 16), ischemic postconditioning group (IPo) (n = 16) and inhibitor of HO-1 group (ZnPP) (n = 16). Donor livers were preserved in 0 - 4 degrees C normal saline, and the period of cold preservation and anhepatic phase were 90 min and 15 min. At 6 h after portal vein reperfusion, blood samples were obtained from the abdominal aorta to determine the level of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), simultaneously liver tissues were taken to determine the level of malondialdehyde (MDA), superoxide dismutase (SOD) and heme oxygenase-1 (HO-1) mRNA. The changes of liver tissues were observed by HE staining and electron microscope. RESULTS: SOD activity was significantly lower whereas MDA content was significantly higher in I/R group than that in Sham group (P < 0.05). The expression of HO-1 in I/R group was higher than that in Sham group (P < 0.05). MDA content was significantly lower whereas SOD activity was significantly higher in IPO group than that in I/R group (P < 0.05), and the expression of HO-1 in IPO group was significantly stronger than that in I/R group (P < 0.05). SOD activity and the expression of HO-1 were significantly lower whereas MDA content was significantly higher in ZnPP group than that in I/R group (P < 0.05). The changes of liver tissues also proved the previous results. CONCLUSIONS: Ischemic postconditioning attenuates liver graft injury induced by I/R in rats. The mechanism might be related with the induction of HO-1 and enhancement of liver graft antioxidation.