缺血预处理对肝硬化大鼠肝脏缺血再灌注中肝细胞凋亡的影响

Effects of ischemic preconditioning on hepatocyte apoptosis induced by hepatic ischemia reperfusion in cirrhotic rats

目的 :探讨缺血预处理 (IPC)在肝硬化大鼠肝缺血再灌注 (I/R)损伤的拮抗作用及其机理。方法 :Pringle法复制肝I/R模型 ,将肝硬化大鼠随机分为 3组 :A组 :肝缺血前给予 1个IPC处理 (缺血 5min ,灌注 5min) ;B组 :肝缺血前给予 1个IPC处理 (缺血 10min ,灌注 10min) ;C组 :对照组 ,单纯肝门血流阻断。肝缺血时间为 30min ,再灌注 6h。测定各组的血清谷丙转氨酶 (ALT)、肝组织Fas mRNA表达、caspase 3活性和肝细胞凋亡。结果 :经IPC处理后 ,大鼠 7d生存率为 10 0 % ,而无IPC处理组即为 6 2 5 %。再灌注 6h ,A、B 2组的ALT明显低于C组 ,P <0 0 1,A组的ALT亦明显低于B组 ,P <0 0 1。检测A、C 2组的肝组织Fas mRNA表达、caspase 3活性和肝细胞凋亡发现 ,A组的上述指标均比C组低 ,P <0 0 1。结论 :IPC对肝硬化大鼠肝I/R损伤有显著的对抗作用 ,其中以缺血 5min和灌注 5min的IPC的作用较强。IPC的保护机理是通过下调Fas mRNA的表达、抑制caspase 3活性 ,从而减少肝细胞凋亡来实现的。

AIM: To investigate the protective effect of ischemic preconditioning (IPC) on hepatic ischemia reperfusion(I/R) injury in cirrhotic rats and its possible mechanism. METHODS: Hepatic I/R was induced by Pringle maneuver. The cirrhotic rats were randomized into three groups: Group A: before 30 min of ischemia, a short period of 5 min ischemia and 5 min reperfusion were given; Group B: before 30 min of ischemia, a short period of 10 min ischemia and 10 min of reperfusion were given; Group C: 30 min ischemia only. The serum alanine transferase (ALT), hepatic Fas mRNA, caspase 3 activity and hepatocyte apoptosis were analyzed. RESULTS: The 7 day survival rate in the group A and B were 100%, respectively. However, it was only 62.5% in the group C. After 6 h of reperfusion, the ALT levels in both group A and B were significantly lower than that of in group C, P <0.01. The ALT level of group A was also lower than that of group B, P <0.01. The hepatic Fas mRNA expression, caspase 3 activity and apoptotic hepatocyte in group A were significantly lower than those of in group C, P <0.01. CONCLUSIONS: IPC has significant protective effect against hepatic I/R injury. An IPC with 5 min of ischemia and 5 min of reperfusion has the maximal protective effect. The protective mechanism of IPC against hepatic I/R injury is via down regulation of Fas mRNA expression, inhibiting caspase 3 activity and subsequently inhibiting hepatocyte apoptosis.