缺血后处理对大鼠肝脏缺血再灌注损伤细胞凋亡的影响

目的：探讨缺血后处理对缺血再灌注损伤大鼠肝脏细胞凋亡的影响。方法：建立大鼠局部肝脏缺血再灌注模型．将24只健康雄性Wistar大鼠随机分为假手术(S)、缺血再灌注(IR)、缺血后处理(IPo)3组，以缺血再灌注前反复多次的短暂预再灌注及停灌注作后处理，观察血清肝酶和肝组织中丙二醛(MDA)、超氧化物歧化酶(SOD)、谷胱甘肽(GSH)水平变化，用末端脱氧核苷酸转移酶介导的dUTP缺口末端标记法(TUNEL)及透射电镜观察肝细胞凋亡状态．并行肝组织病理形态学检查。结果：与IR组相比，IPo组血清肝酶水平及肝组织中MDA含量显著降低，而SOD和GSH活性则显著升高；再灌注后可见明显的肝实质细胞凋亡现象，IPo组凋亡指数较IR组显著下降，肝组织病理形态学损伤亦明显减轻。结论：IPo可通过抑制再灌注后氧自由基的过量生成而拮抗肝实质细胞凋亡的发生，从而减轻肝脏缺血再灌注损伤。

The Role of Post-ischemic Conditioning on Cell Apoptosis in Rat Livers with Ischemia-reperfusion Injury

Objective: To investigate the effect of post-ischemia conditioning on cell apoptosis in rat livers with ischemia-reperfusion injury. Methods: Using a rat model of acute liver ischemia-reperfusion, 24 healthy male Wistar rats were randomly divided into 3 groups: sham-operated (S group), ischemia-reperfusion (IR group) and post-ischemia conditioning (IPo group). IPo was achieved by several brief episodes of reperfusion before the persistent reperfusion procedure. The activity of plasma enzyme and the concentration of malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione (GSH) in hepatic tissue were measured respectively. The status of hepatocellular apoptosis was detected by TdT-mediated dUTP-biotin nick end labeling (TUNEL) and electronic microscropy in all groups. Results: Compared with the IR group, the activity of plasma enzyme and the concentration of MDA in hepatic tissue in the IPo group were reduced markedly, while the activity of SOD and GSH was enhanced markedly. There were obvious hepatocellular apoptosis after reperfusion and the apoptotic index in the IPo group was significantly lower than that of the IR group. Conclusions: IPo could depress the synthesis of oxygen free radicals and reduce hepatocellular apoptosis after reperfusion, and thus produce a protective effect on hepatic ischemia-reperfusion injury.