大鼠实验性心肌缺血再灌注时心肌细胞凋亡的动态变化及意义

Dynamic changes and its implication of myocardial Cell apoptosis in rats with experimental myocardial ischemia/reperfusion

探讨大鼠心肌缺血再灌注时心肌细胞凋亡的动态变化及其与心肌缺血再灌注损伤的相互关系。结果显示假手术组与心肌缺血１５ｈ未见心肌细胞凋亡，但缺血３５ｈ或缺血３０ｍｉｎ再灌注ｌｈ已见有细胞凋亡，细胞凋亡出现明显早于细胞坏死。细胞凋亡指数（ＡＩ）随缺血或再灌注时间延长呈渐增趋势，分别以缺血４８．５ｈ（４９８％士１７．２７％）和缺血３０ｍｉｎ再灌注４８ｈ（３８．１５％±１３．２６％）最高。与心肌缺血组比较，心肌缺血再灌注组相同处理时间的大鼠的ＡＩ较低（Ｐ＜０．０５）。凋亡细胞主要位于心肌纤维收缩带区域及心肌梗死区周围。电镜示再灌注；０肌组织中有典型细胞凋亡形态改变。研究提示心肌细胞凋亡是持续性心肌缺血中早期心肌细胞死亡的主要形式，再灌注过程虽减少凋亡细胞数量，但却促进了不可逆损伤的心肌细胞的凋亡过程。

In this articl e, we studied the dynamic changes of myocardial cell apoptosis and its relationship with myocardial ischemia/reperfusion injury (MIRI ) in rat models with MId. The results showed that no evidence of myocyte apoptosis was found in myocardium with sham-operated control and 1 .sh of MI, but the rats displayed signs of myocyte apoptosis in myocardium with 3.5h of MI or 30min of MI followed lh of reperfusion. Apoptosis appeared earlier than necrosis in myocytes. Apoptotic index (AI) increased with duration of ischemia or reperfusion, and were highest at 48.5h of MI (49.82% ±17.27% ) in MI group and at 48h ofreperfusion after 30min of MI (38.15 % ±13.26 % ) in MIR group respectively. Compared with MI group, the values ofAl were lower in MIR group at the same experimental duration with MI group (P<0.05). Apoptotic myocytes were main ly localized in the areas of contraction bands and the border zones of infarcted and noninfarcted myocardium. The typically morphological changes ofmyocyte apoptosis were observed by transmission electron microscope in myocardium with MIR. These data suggest that myocyte apoptosis appears to constitute the predominant early form of myocyte death in myocardium with continuous ischemia. Although reperfusion process decreased the amount of apoptotic myocytes, it accelerates apoptosis in the nonsalvageble cells due to ischemia.