2,3-丁二酮单肟改善大鼠离体心脏钙反常损伤的作用及机制

摘要

目的：探讨挛缩抑制剂2,3-丁二酮单肟（2,3-butanedione monoxime, BDM）改善大鼠离体心脏钙反常损伤的作用及其机制。方法32只SD雄性大鼠随机分为4组：正常对照组、BDM对照组、钙反常组和BDM干预组。大鼠离体心脏行Langendorff灌流，记录左室内压（left ventricular pressure, LVP）、左室舒张末压（left ventricular end-diastolic pressure, LVEDP），并计算左室发展压（left ventricular developed pressure, LVDP）评价心功能；测定复灌期冠脉流出液中乳酸脱氢酶（LDH）的含量反映心肌损伤；2、3、5-氯化三苯基四氮唑（TTC）染色法评价心肌梗死面积的变化；TUNEL法检测心肌细胞凋亡指数；Western blot法检测cleaved caspase-3和细胞色素c（cytochrome c）蛋白的表达。结果与正常对照组相比，BDM（20 mmol/L）对照组大鼠心脏左室功能、心肌梗死面积和凋亡指数及cleaved caspase-3和细胞色素c蛋白的表达，无显著性变化（P>0.05）；钙反常组LVEDP显著抬升，LVDP为0，冠脉流出液中LDH含量明显增多（P<0.01），cleaved caspase-3和细胞色素c蛋白的表达以及凋亡指数明显增加（P<0.01），心脏组织几乎全部死亡（P<0.01）；BDM（20 mmol/L）干预钙反常组大鼠心脏心梗面积显著减小（P<0.01），LVEDP降低、LVDP部分恢复（P<0.01），LDH释放减少（P<0.01），cleaved caspase-3和细胞色素c蛋白表达量以及凋亡指数明显降低（P<0.01）。结论 BDM明显抑制急性钙超载引起的挛缩和细胞凋亡，改善心功能，减轻大鼠离体心脏钙超载损伤，是一种潜在的缺血再灌注心肌保护药物。%Objective To investigate the Effect of 2,3-butanedione monoxime (BDM) on calcium paradox-induced heart injury and its underlying mechanisms. Methods Thirty-two adult male SD rats were randomized into 4 groups, namely the control group, BDM treatment control group, calcium paradox group, and BDM treatment group. Isolated Sprague Dawley male rat hearts underwent Langendorff perfusion and the left ventricular pressure (LVP) and left ventricular end-diastolic pressure (LVEDP) were monitored. Left ventricular developed pressure (LVDP) was calculated to evaluate the myocardial performance. Lactate dehydrogenase (LDH) content in the coronary flow was determined. Triphenyltetrazolium chloride staining was used to measure the infarct size, and myocardial cell apoptosis was tested with TUNEL method. Western blotting was used to determine the expression of cleaved caspase-3 and cytochrome c. Results Compared with the control group, BDM at 20 mmol/L had no effect on cardiac performance, cell death, apoptotic index or the content of LDH, cleaved caspase-3 and cytochrome c at the end of perfusion under control conditions (P>0.05). Calcium paradox treatment significantly decreased the cardiac function and the level of LVDP and induced a larger infarct size (P<0.01), an increased myocardial apoptosis index (P<0.01), and up-regulated expressions of cleaved caspase-3 and cytochrome c (P<0.01). BDM (20 mmol/L) significantly attenuated these effects induced by calcium paradox, and markedly down-regulated the levels of LVEDP and LDH (P<0.01), lowered myocardial apoptosis index, decreased the content of cleaved caspase-3 and cytochrome c (P<0.01), increased LVDP, and reduced the infarct size (P<0.01). Conclusion BDM suppresses cell apoptosis and contracture and improves heart function and cell survival in rat hearts exposed to calcium paradox, suggesting the value of BDM as an potential drug for myocardial ischemia reperfusion injury.