Estrogen pretreatment upregulats estrogen receptor expression in rats with hepatic ischemia/reperfusion injury

OBJECTIVE To investigate the effect of estrogen pretreatment on estrogen receptor(ER) expression in hepatic ischemia/reperfusion injury(I/R) in rats.METHODS A hepatic I/R model was constructed using Pringle′s method.Estradiol 4 mg·kg-1 was injected intraperitoneally before hepatic ischemia.The level of serum alanine aminotransferase(ALT) and tumor necrosis factor-α(TNF-α) levels,nuclear factor(NF)-κB and estrogen receptor α(ERα) expression,and hepatic tissue were measured pre-ischemia(R0),post-reperfusion 1 h(R1),3 h(R3),6 h(R6) and 24 h(R24).RESULTS The levels of ALT and TNF-α and the expression of NF-κB and ERα in I/R group and estrogen+I/R group were increased compared to sham group.The level of ALT in R6 were increased 11.7 times and 8.1 times in I/R and estrogen+I/R groups compared to sham group.The level of TNF-α at R6 was increased 5.2 and 3.2 times compared to sham group,but the increase in I/R group was more significant than in estrogen+I/R group.The expression of NF-κB increased 8.6 and 4.8 times of I/R and estrogen+I/R group compared to sham group at R6,the expression of ERα was increased 4.2 and 7.4 times,but the degree increased of estrogen+I/R group was more marked than in ERα of I/R group.The liver damage in I/R group was more severe than that of estrogen+I/R group.CONCLUSION Estrogen pretreatment can decrease the levels of ALT and TNF-α and the expression of NF-κB,and alleviate hepatic I/R injury by upregulation of ERα expression.