Nrf2/ARE信号通路在肢体缺血后处理减轻大鼠肝脏缺血再灌注损伤中的作用

摘要

目的 探讨转录因子NF-E2相关因子2(nuclear factor erythroid2-related factor 2, Nrf2)/抗氧化反应元件(antiox-idant response element, ARE)Nrf2/ARE信号通路在肢体缺血后处理减轻大鼠肝脏缺血再灌注损伤中的作用.方法 健康雄性SD大鼠24只,体重240～300g,采用随机数字表法分为3组(每组n=8):假手术组(S组)、缺血再灌注组(I/R组)、肢体缺血后处理组(LIPC组).I/R组和LIPC组采用无损伤小动脉夹阻断支配肝左、中叶的门静脉、肝动脉30min后再灌注120min的方法制备肝脏缺血再灌注损伤模型;LIPC组于肝脏缺血后20min行大鼠双侧肢体缺血10min.于再灌注120min时采集下腔静脉血3mL测定血清谷草转氨酶(AST)、谷丙转氨酶(ALT)的活性,随后处死所有大鼠取肝左叶边缘组织,电镜下观察肝细胞的超微结构,并采用Western blot方法检测肝组织中Nrf2、低氧诱导因子-1α(HIF-1α)及血红素氧合酶(HO-1)蛋白的表达.结果 与S组比较,I/R组和LIPC组血浆ALT和AST活性升高(P＜0.01),肝细胞超微结构损伤明显;与I/R组比较,LIPC组血清ALT和AST活性均降低(P均＜0.01),肝脏超微结构损伤减轻.I/R组、LIPC组的肝组织Nrf2、HIF-1α及HO-1蛋白表达均高于S组,且LIPC组高于I/R组(P均＜0.05).结论 肢体缺血后处理可减轻大鼠肝脏缺血再灌注损伤,与Nrf2/ARE信号通路有关.%ObjectiveTo explore the role of Nrf2/ARE signaling pathway in reduction of hepatic ischemia-reperfusion (I/R) injury by limb ischemic postconditioning (LIPC) in rats.MethodsTwenty-four healthy male Sprague-Dawley rats, weighing 240-300g, were randomly divided into 3 groups (n=8) using a random number table:sham operation group (group S), ischemia reperfusion group (group I/R), limb ischemic postconditioning group (group LIPC).The hepatic ischemia-reperfusion injury model was established in I/R group and LIPC group by blocking the portal vein innervating the left and middle lobes of the liver and reperfusion 120 minutes after 30 minutes of the hepatic artery.In LIPC group, bilateral limbs were ischemic for10 minutes after 20 minutes of the hepatic ischemia.The activities of serum glutamic oxaloacetic transaminase (AST) and alanine transaminase (ALT) were measured at 3mL of inferior vena cava blood at 120 minutes of reperfusion.All rats were killed and the marginal tissue of left lobe of liver was taken.The ultrastructure of hepatocytes was observed under electron microscope.The expression of Nrf2, HIF-1a and HO-1 protein in liver tissue was detected by Western blot.ResultsCompared with group S, theactivities of serum ALT and AST plasmasignificantly increased (P＜0.01), and the damage to the ultrastructure of hepatocytes was obvious in group I/R and group LIPC.Compared with group I/R, the plasma ALT and AST activities significantly decreased (P＜0.01), and the damage to the ultrastructure of hepatocytes reduced in group LIPC.The expressions of Nrf2, HIF-1alpha and HO-1 in liver tissue of I/R group and LIPC group were higher than those of S group, and there were higher in LIPC group than that in I/R group (P＜0.05).Conclusion Limb ischemic postconditioning can attenuate liver ischemia-reperfusion injury in rats by activating the Nrf2/ARE signaling pathway.