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目的研究急性心肌梗死后急性高血糖对大鼠心肌细胞线粒体超微结构和膜电位的影响。方法结扎40只雄性SD大鼠左冠状动脉前降支建立急性心肌梗死模型后随机分为4组:对照组、高糖1组、高糖2组和胰岛素组,另取10只SD大鼠设为假手术组,术中监测血糖水平,实验终点观察各组大鼠心肌细胞凋亡指数、线粒体和胞浆内细胞色素C表达以及线粒体超微结构和膜电位变化。结果与假手术组相比较,余各组细胞凋亡指数均增高,线粒体超微结构均不同程度损失变化,线粒体膜电位均降低;胞浆细胞色素C表达增加而线粒体内细胞色素C表达减少(P<0.05)。与高糖2组相比,其余各组细胞凋亡指数显著减低,线粒体超微结构损伤程度较轻,线粒体膜电位显著增高,细胞色素C胞浆表达显著减少而线粒体表达显著增加(P<0.05)。结论急性心肌梗死后急性高血糖可能通过损伤线粒体显著促进细胞凋亡,注射胰岛素降低血糖能有效地减少细胞凋亡。
Objective To investigate the effects of acute hyperglycemia on mitochondrial ultrastructure and membrane potential in rat myocardial cells after acute myocardial infarction. Methods Acute myocardial infarction model was established in 40 male SD rats with left anterior descending coronary artery. The rats were randomly divided into 4 groups: control group, high glucose group 1, high glucose group 2 and insulin group, and another 10 SD rats In the sham operation group, the intraoperative blood glucose level was monitored. The apoptotic index, the expression of cytochrome C in mitochondria and cytoplasm, and the changes of mitochondrial ultrastructure and membrane potential were observed at the end of the experiment. Results Compared with the sham-operated group, the apoptosis index of the other groups were increased, the ultrastructure of mitochondria were all changed to varying degrees, mitochondrial membrane potential were decreased, cytoplasmic cytochrome C expression increased and mitochondrial cytochrome C expression decreased P <0.05). Compared with the high glucose group, the apoptotic index of the other groups was significantly decreased, mitochondrial ultrastructure damage was mild, mitochondrial membrane potential was significantly increased, cytochrome C cytoplasm was significantly reduced and mitochondrial expression was significantly increased (P <0.05 ). Conclusion Acute hyperglycemia after acute myocardial infarction may significantly promote apoptosis through mitochondria injury. Injecting insulin to reduce blood glucose can effectively reduce apoptosis.