一氧化氮及caspase-3表达与暴发性肝衰竭细胞凋亡

目的:研究一氧化氮(NO)及caspase-3表达在暴发性肝衰竭(FHF)中与肝细胞凋亡的关系.方法:检测FHF模型小鼠及给予iNOS抑制剂L-NMMA后不同时间肝组织caspase-3表达、血清NO水平、肝组织iNOSmRNA表达及肝细胞凋亡的变化.结果:FHF模型小鼠于4 h时NO表达达高峰,以后逐渐下降,8 h可出现典型的肝细胞凋亡表现,caspase-3表达至最高峰;12 h caspase-3表达较8 h减少,肝细胞坏死和凋亡同时存在.阻断NO后,NO表达为正常水平,caspase-3表达较模型组无显著差异,阻断后8 h亦可见典型的DNA梯形带,12 h亦出现坏死带.阻断NO后肝组织病变较模型组更为严重.结论:在FHF中,拮抗NO作用不能阻断肝细胞凋亡和肝脏生化学及组织学变化,提示单纯应用NO拮抗剂对肝细胞凋亡及肝损伤无保护作用.NO可能抑制caspase-3的表达及肝细胞凋亡的发生.

Nitric oxide and caspase-3 expression with apoptosis in fulminant hepatic failure

Objective: To study the relationship of nitric oxide (NO) and expression of caspase-3 with hepatocyte apoptosis in fulminant hepatic failure (FHF).Methods:The expression of caspase-3, level of serum NO,iNOS mRNA expression in liver, and hepatocyte apoptosis were determined in the different stage after drug administration in experimental model of mice with FHF. We observed the changes of above indexes after pretreatment with L-NMMA ,an inhibitor of inducible nitric oxide synthase.Results:The level of nitric oxide reached the peak at the 4th hour and then gradually decreased. There was typical manifestation of hepatocyte apoptosis at the 8th hour after drug administration. The expression of caspase-3 reached the peak. There were hepatocyte apoptosis and necrosis at the 12th hour after drug administration and the expression of caspase-3 decreased. The level of NO was normal, and there was no statistical difference in expression of caspase-3 compared with that before blocking .There was typical DNA ladder at the 8th hour and necrosis band at the 12th hour after L-NMMA administration. The histology of liver tissue after blocking was more severe than that of model group.Conclusions:The abnormal changes of biochemistry and histology and hepatocyte apoptosis could not be blocked after single antagonization of NO in FHF. Nitric oxide did not play protective role in hepatocyte apoptosis and liver injury after L-NMMA administration in FHF.NO may inhibit the expression of caspase-3 and hepatocyte apoptosis.