目的　为证实急性心肌缺血再灌注过程中存在着不同程度的心肌细胞凋亡现象 ,初步研究心肌细胞凋亡与Bcl 2 /Bax蛋白表达的关系。　方法　透射电镜观察心肌细胞的超微结构变化 ,抽提心肌组织DNA琼脂糖凝胶电泳 ,TUNEL法原位标记凋亡的心肌细胞 ,免疫组织化学技术和图像分析技术检测心肌细胞内Bcl 2 /Bax蛋白表达。　结果　缺血及再灌注组电镜观察心肌细胞出现典型凋亡超微结构特征 ,TUNEL染色可见不同程度的心肌细胞凋亡阳性反应 ,DNA电泳显示在缺血再灌注 2h出现明显的DNA条纹图像 ,再灌注组较缺血组心肌细胞中Bcl 2表达明显降低 (P <0 0 5 ) ,而Bax表达显著增高 (P <0 0 1)。　结论　急性心肌缺血及再灌注能诱导不同程度的心肌细胞凋亡 ,Bcl 2 /Bax基因对心肌细胞凋亡的发生有着重要的调控作用 Objective To investigate the apoptosis of cardiomyocytes in acute myocardial ischemia-reperfusion injury and to study the relationship between cardiomyocyte apoptosis and Bcl 2 / Bax protein expression. Methods The ultrastructural changes of myocardial cells were observed by transmission electron microscopy. The myocardial tissue was extracted by DNA agarose gel electrophoresis. TUNEL method was used to label apoptotic cardiocytes in situ. Immunohistochemistry and image analysis were used to detect the expression of Bcl 2 / Bax Protein. Results The ultrastructural changes of myocardial cells were observed by electron microscopy under electron and electron microscope. TUNEL staining showed different degrees of apoptosis in cardiomyocytes. DNA electrophoresis showed obvious DNA streak images at 2 hours after ischemia / reperfusion. Compared with ischemia group, Bcl-2 expression was significantly decreased (P <0.05) and Bax expression was significantly increased in perfusion group (P <0.01). Conclusion Acute myocardial ischemia and reperfusion can induce cardiomyocyte apoptosis in different degree, and Bcl 2 / Bax gene plays an important regulatory role in cardiomyocyte apoptosis