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目的 为探讨细胞凋亡在急性心肌梗塞时心肌细胞中的意义。方法 用末端原位标记 (TUNEL)法、DNA电泳和电镜三种方法检测兔急性心梗模型中梗塞区心肌细胞的凋亡。结果 TUNEL法发现 :兔急性心梗模型中梗塞区心肌细胞凋亡千分率在冠脉结扎前 (0h)和结扎后 1h、2h、3h、4h、6h、8h、12h的改变如下 :0h组 (31 0 0± 14 0 0‰ )和 12h组 (6 8 0 0±31 72‰ ) <1h组 (142 33± 5 3 5 2‰ ) <2h组 (370 83± 6 6 0 1‰和 8h组 (32 1 17± 86 43‰ ) <3h组 (5 86 83± 5 5 0 2‰ ) <4h组(836 17± 43 73‰ ) (P均 <0 0 5 ) ,即急性心梗心肌细胞凋亡数在冠脉结扎后 1h时开始逐渐增多 ,到 4h时达高峰 ,其后逐渐下降 ,到 12h时已逐渐降至正常。DNA梯形电泳显示在兔冠脉结扎后 3h、4h、6h时梗塞区的心肌细胞均出现相差约 180～2 0 0bp的DNA阶梯 (Ladder) ,而其它各时间点的心肌细胞未见有相差约 180～ 2 0 0bp的DNA条带。电镜观察显示在兔冠脉结扎后梗塞区内的心肌细胞核膜完整、染色质浓集、电子密度增加的凋亡特征 ,有的则出现核膜破裂、染色质溶解成碎屑的坏死现象。结论 兔冠脉在结扎 3～ 6h时梗塞的心肌细胞凋亡特征最明显 ,细胞凋亡在急性心梗心肌细胞死亡中起重要作用。
Objective To investigate the significance of apoptosis in cardiomyocytes in acute myocardial infarction. Methods TUNEL, DNA electrophoresis and electron microscopy were used to detect the apoptosis of infarcted myocardium in rabbits with acute myocardial infarction. Results TUNEL assay showed that the percentages of cardiomyocyte apoptosis in acute myocardial infarction model in rabbits before ischemia (0h) and 1h, 2h, 3h, 4h, 6h, 8h and 12h after ligation were as follows: (31 0 0 ± 14 0 0 ‰) and 12 h group (6 8 0 ± 31 72 ‰) <1 h group (142 33 ± 5 3 5 2 ‰) <2 h group (370 83 ± 6 6 0 1 ‰ and 8 h (32 1 17 ± 86 43 ‰) <3h group (5 86 83 ± 5 5 0 2 ‰) <4h group (836 17 ± 43 73 ‰) (all P 0 05), that is, acute myocardial infarction The number of apoptotic cells began to increase at 1h after coronary ligation and peaked at 4h, then gradually decreased to normal after 12h, and DNA ladder electrophoresis showed that at 3h, 4h and 6h after coronary artery ligation There was a DNA ladder with difference of about 180 ~ 200 bp in myocardial cells in infarction area, but there was no DNA bands of about 180 ~ 200 bp in myocardial cells at other time points.Electron microscopy showed that in rabbit’s coronal The myocardial cells in the infarct area after the ligation of the vein were complete with nuclear membrane integrity, chromatin condensation and electron density increase, while others showed rupture of the nuclear membrane and chromatin dissolution into debris necrosis.Conclusion Rabbit coronary artery Myocardial apoptosis was the most obvious at 3 ~ 6h after ligation, and apoptosis played an important role in cardiomyocyte death in acute myocardial infarction.