糖尿病大鼠心肌缺血再灌注损伤变化及Cyt C和Caspase-3的表达

目的探索高血糖状态下，急性心肌缺血诱导心肌细胞凋亡的程度变化及其可能机制。方法TUNEL法检测糖尿病大鼠IRI心肌细胞凋亡的程度，应用免疫组化染色技术检测大鼠心肌细胞色素C（Cyt C）和Caspase-3的表达。结果随心肌缺血再灌注时间的延长，糖尿病（DM）组AI呈逐渐上升的趋势，非糖尿病（NDM）组AI呈先上升再下降的趋势；缺血30min后再灌，6h内DM组大鼠Cyt C和Caspase-3的阳性表达率或阳性强度均明显低于NDM组；24h时DM组大鼠Cyt C和Caspase-3的阳性表达率或阳性强度均明显高于NDM组；Cyt C和Caspase-3的表达与AI值呈正相关。结论DM组大鼠心肌IR后24h内，心肌细胞Cyt C和Caspase-3阳性表达增加发生延迟，持续时间长；相同时相，糖尿病大鼠心肌IRI细胞凋亡较非糖尿病大鼠减轻的可能机制为细胞色素C释放和Caspases激活的生物化学途经发生耐受。

The variation of injury degree and expression of Cytochrome C and Caspase-3 during myocardial ischemia reperfusion in diabetic rats

Objective To explore the variation and mechanism of in vivo myocardial cell apoptosis induced by acute IRI in hyperglycemia state. Methods Myocardial apoptosis at different phases during IRI in diabetic rats in vivo were examined by TUNEL. The expression of Cytochrome c and Caspase-3 were examined with immunohistochemistry staining technique. Results With prolongation of reperfusion, the AI in Group DM increased gradually, while in Group NDM the AI increased at first and then decreased. Within 6 hours of reperfusion, the positive rate or positive magnitude of Cytochrome c and Caspase-3 in DM group was significantly less than that in NDM group, while the result was just opposite at 24h of reperfusion. The positive rate of Cytochrome c and Caspase-3 was positively correlated with AI. Conclusion Compared with NDM group, the positive expression of Cytochrome c and Caspase-3 increased more late and slowly within 24 hours. At the same phase, the reason that the apoptosis of group DM is not so serious as that in NDM group may be due to tolerance generation caused by Cytochrome c release and activation of Caspase-3 .