大鼠心肌缺血再灌注时心肌细胞凋亡caspase-3活性变化规律及药物对其影响

目的　探讨大鼠心肌缺血再灌注 (Ischemiareperfusion ,IR)不同时相的心肌细胞凋亡、caspase 3活性变化规律及caspase 3抑制剂Ac DEVD CHO的影响。方法　Wistar大鼠 12 2只 ,设立IR组 ,IR +Ac DEVD CHO组和假手术对照组并分设缺血 3 0min后再灌注 1、3、6、12、2 4h 5个时相点 ;以缺口末端标记法 (TUNEL)标记凋亡细胞 ,用荧光分析法检测caspase 3活性 ,行TTC染色测定心肌梗死范围。结果　心肌细胞凋亡与caspase 3活性随心肌再灌注不同时相而变化 ,心肌细胞凋亡指数 (Apoptosisindex ,AI)与caspase 3活性于再灌注 12h最高 AI :( 3 4 83± 9 3 5 ) % ;caspase 3活性 :( 1 3 4±0 2 ) ] ,其后基本维持在平台状态 ;心肌梗死范围随IR时间逐渐增加 ,至 2 4h仍未见下降趋势 ,三者间呈显著正相关 (P <0 0 5 )。IR +Ac DEVD CHO组上述指标虽也明显增高 ,但比IR组明显减小 (P <0 0 5 )。结论　Caspase 3激活及心肌细胞凋亡参与了心肌缺血再灌注损伤过程 ,Ac DEVD CHO减轻心肌缺血再灌注损伤可能部分与其抑制心肌细胞凋亡有关。

Changes of apoptosis and caspase-3 activity and the effects of Ac-DEVD-CHO in cardiomyocytes of rats with myocardial reperfusion injury

Objective To observe the changes of apoptosis and caspase 3 activity in cardiomyocytes of rats at different time points after transient ischemia and the effects of caspase 3 inhibitor Ac DEVD CHO on reperfusion injury Methods A total of 122 rats were divided randomly into 3 groups: IR group, IR+Ac DEVD CHO group and sham group The ischemic samples were observed at 30 min after ischemia followed by reperfusion at 1, 3, 6, 12 and 24 h The apoptotic cardiomyocytes, the activity of caspase 3 and the myocardial infarction area were determined by TUNEL method, fluorescent assay and TTC dyeing method, respectively Results Apoptosis index(AI) of cardiomyocyte and caspase 3 activity changed in a time dependent manner Highest AI and caspase 3 were found after reperfusion at 12 h The myocardial infarction area in group IR kept increasing during the period of reperfusion AI and caspase 3 activity were positively correlated with the myocardial infarction area( P <0 05) In IR+Ac DEVD CHO group, all indexes increased after IR but were significantly lower than those in group IR( P <0 05) Conclusion Apoptosis and activation of caspase 3 may be involved in the process of myocardial ischemia/ reperfusion injury Ac DEVD CHO is effective in attenuating myocardial reperfusion injury, which partially attributes to the inhibition of cardiomyocyte apoptosis