鼠肝缺血再灌注Fas-mRNA、Caspase-3变化及缺血预处理作用机制

目的探讨Fas介导细胞凋亡上游Fas mRNA表达和下游Caspase3活性在鼠肝缺血再灌注(IschemicReperfusion,IR)损伤中的变化及缺血预处理(IschemiaPreconditioning,IP)的保护作用机制。方法45只大鼠随机分为IR组、IP组及假手术组(S)组。检测再灌注术后3h血清AST,ALT水平、肝组织Fas mRNA表达、Caspase3活性、肝细胞凋亡指数(ApoptosisIndex,AI)和电镜下超微结构改变。结果(1)血清AST,ALT改变:IP组和IR组较S组显著升高(P<001),其中IR组升高最明显,与IP组比较差异有显著性(P<0.01)。(2)肝组织Fas mRNA表达、Caspase3活性,IR组和IP组较S组明显升高(P<0.01),IR组最明显,与IP组比较差异显著(P<0.01),而3组IR前各指标比较均差异无显著性(P>0.05)。(3)肝细胞AI与Fas mRNA表达、Caspase3活性均呈正相关,S组未见明显凋亡细胞,IR组和IP组AI差异有显著性(P<0.01)。(4)电镜IR组超微结构破坏明显,IP组相对较轻,S组基本正常。结论IR损伤可增强Fas mRNA表达、激活Caspase3活性,共同促进肝细胞凋亡,从而加重肝脏损害,IP可明显减轻肝脏IR损伤,机制之一是下调Fas介导细胞凋亡上游Fas mRNA表达和下游Caspase3活性来抑制肝细胞凋亡。

The Expression of mRNA of Fas and Caspase-3 Activity of Ischemic Re-perfusion Injury in Rats and the Protective Mechanism of Ischemic Preconditioning

Objective To explore mRNA expression of Fas and Caspase-3 activity in the ischemia re-perfusion injury in rats and the protective effect of ischemic preconditioning and its possible mechanism. Methods Forty-five rats were at random assigned to ischemia re-perfusion (IR) group, ischemic preconditioning (IP) group, and sham operation (S) group. The serum aspartate transaminase (AST), alanine transaminase (ALT), liver mRNA expression of Fas, Caspase-3 activity, apoptosis index of hepatocytes and transformed microstructure were respectively examined in the three groups in three hours after re-perfusion. Results The serum AST, ALT, liver mRNA expression of Fas and Caspase-3 activity, apoptotic hepatocytes were significantly higher in both IP and IR groups than in S groups (P<0.01), and those in group IR were significantly increased when compared with those in group IP (P<0.01). There was a positive correlation between AI and the increase of mRNA expression of Fas or Caspase-3 activity. Electron microscope displayed that the damage of organelles in IP group was less than that in IR group, while no change of organelles was found in S group. Conclusion IR injury may activate the apoptosis of hepatocytes by increasing mRNA expression of Fas and Caspase-3 activity, and lead to aggravating the injury of liver. IP may reduce IR injury of liver and its possible mechanism is to inhibit hepatocytes' apoptosis by down-regulating mRNA expression of Fas and Caspase-3 activity.