缺血/再灌注所致心肌细胞凋亡的综合监测

INTEGRATED MEASUREMENTS FOR APOPTOSIS OF CARDIOMYOCYTES INDUCED BY ISCHEMIA/REPERFUSION

目的确定细胞凋亡参与心肌缺血 /再灌注损伤 ,观察凋亡相关基因 (Bcl 2、Bax和Fas)表达的变化。方法在 12只雄性家兔心脏缺血 /再灌注模型上 ,监测血流动力学、心外膜电图和心肌梗死范围。由原位末端标记法和凝胶电泳法确定心肌细胞凋亡 ;流式细胞分析法测定细胞凋亡率以及Bcl 2、Bax和Fas表达量。结果在缺血/再灌注过程中 ,心率、血压和心肌耗氧量均持续性下降 ;心外膜电图ST段在缺血期明显抬高 ,再灌注时逐渐恢复正常。心肌梗死范围占缺血心肌的 (5 7.7± 2 .0 ) %。原位末端标记法显示 ,缺血区存活心肌中有大量凋亡细胞 ,且缺血区心肌凝胶电泳上呈典型的云梯状 ,细胞凋亡率为 (11.2± 0 .4) % ,Bax和Fas表达较非缺血区增高。结论缺血 /再灌注可使心肌细胞发生凋亡 。

ObjectiveTo determine the contribution of apoptosis to myocardial injury induced by ischemia/reperfusion and to observe the expression of Bcl 2, Bax and Fas which involved in apoptosis. MethodsTwelve male rabbits were subjected to myocardial ischemia/reperfusion. The hemodynamics and epicardial electrography were recorded and myocardial infarct size was examined with nitro blue tetrazolium chloride. Apoptosis was detected with an in situ end labeling method and DNA on agarose gel electrophorsis. Apoptosis rate and expression of Bcl 2, Bax and Fas were measured by flow cytometry. ResultsDuring the course of myocardial ischemia/reperfusion, heart rate, blood pressure and myocardial oxygen consumption decreased progressively. The epicardial electrographic ST segment was elevated significantly during ischemia, and recovered to baseline during reperfusion. The myocardial infarct size occupied ( 57.7 ± 2.0 ) % of the ischemic myocardium. Apoptotic cardiomyocytes were found within the ischemic myocardium at risk. In ischemic myocardium, DNA ladder pattern was revealed by agrose gel electrophoresis, apoptosis rate was ( 11.2 ± 0.4 ) % , and expression of Bax and Fas was higher than that in non ischemic myocardium , but Bcl 2 expression had no change. ConclusionMyocardial ischemia/reperfusion induces apoptosis of cardiomyocyte, and the overexpression of Bax and Fas may accelerate the apoptosis.