Effects of 17-.BETA. estradiol on regeneration of the remnant liver after semi-hepatectomy with 45 minutes of hepatic ischemia in rats

Objective To investigate whether 17-βestradiol can promote regeneration of the remnant liver after semi-hepatectomy with 45 minutes of hepatic ischemia in rats.Methods Male Sprague-Dawley rats were randomly allocated into 3 groups:R group,rats subjected to 50％ hepatectomy alone;R + IR group,rats subjected to 50％ hepatectomy and 45min of hepatic ischemia; E2 + R + IR group,rats administration with 17-βestradiol.The 7d survival rate,serum alanine aminotransferase (ALT) level,liver histology and remnant liver regeneration were then investigated.Results Compared with R + IR group,17-βestradiol significantly improved the 7 d survival rate (80％ vs 20％,P ＜ 0.05),decreased ALT levels (P ＜0.05) and increased the RLW (P ＜0.05).The pathological changes at 12h after reperfusion were milder and the expression of Ki-67,proliferating cell nuclear antigen (PCNA) and Cyclin D1 in the 2d after reperfusion were significantly higher in E2 + R + IR group comparison to those in the R + IR group.Conclusion 17-βestradiol could promote regeneration of the remnant liver after semi-hepatectomy with 45 minutes of hepatic ischemia in rats.The high expression of Cyclin D1 may be one of the reasons. Key words: Estrogen ;  Ischemia-reperfusion injury ;  Hepatectomy ;  Liver transplantation ; Cyclin D1