极端热环境心肌细胞损伤乳鼠心肌细胞凋亡与Bim及caspase-3蛋白的表达

Expression of pro-apoptotic protein Bim and caspase-3 during hyperthermia-induced cardiomyocytes apoptosis of neonate rats

背景:目前有关极端气候条件下疾病发生规律、机制及防治措施的研究,国内只有零星报道,均为病理生理表现的研究,尚未深入到分子机制的研究。目的:观察前凋亡蛋白Bim及caspase-3在极端热环境致乳鼠心肌细胞损伤中的作用。方法:体外培养1～3d龄SD大鼠心肌细胞,建立心肌细胞热环境损伤模型(42℃,60min)。观察热处理后恢复37℃孵育0,4,8,12,16,24h时心肌细胞损伤情况。倒置显微镜下观测各组心肌细胞搏动频率和节律;MTS/PMS法检测细胞存活率;全自动生化分析仪测定心肌细胞培养液乳酸脱氢酶活性;AnnexinV-FITC/PI双染流式细胞术检测细胞凋亡率;Western blot检测Bim及caspase-3蛋白表达。结果与结论:体外培养乳鼠心肌细胞热处理后即刻(0h)搏动频率略有增加,并可见异常节律,此后随时间的延长心肌细胞搏动频率逐渐减慢,存活率下降(P<0.05),乳酸脱氢酶活性升高(P<0.05);恢复37℃孵育8h时前凋亡蛋白Bim显著升高(P<0.05);caspase-3从恢复37℃孵育时表达即明显升高(P<0.05)。因此,提示极端热环境使心肌细胞发生了损伤,且以凋亡为主要损伤形式,前凋亡蛋白Bim与caspase-3可能参与了极端热环境致乳鼠心肌细胞凋亡的过程。

BACKGROUND：In China,the occurrence rule,mechanisms and prevention measures of diseases under extreme weather are few reported,and which only focused on pathophysiological manifestation rather than molecular mechanism level.OBJECTIVE：To explore the role of pro-apoptotic protein Bim and caspase-3 in hyperthermia-induced cardiomyocyte apoptosis.METHODS：Cardiomyocytes of Sprague Dawley rats with 1-3 days were exposed to hyperthermia（42 ℃,60 min） environment.The degree of cell damage was observed at 0,4,8,12,16,and 24 hours after recovery.The beating rate and rhythm of myocardial cells were detected by inverted microscope.The cell viability was determined by AnnexinV-FITC/PI.The activity of lactate dehydrogenase was determined by automatic biochemistry analyzer.In addition,the expression of Bim and caspase-3 protein was tested by Western blot analysis.RESULTS AND CONCLUSION：The beating rate of myocardial cells was slightly increased at immediately after recovery,gradually decreased with time prolonged,and the cell viability was decreased（P〈0.05）;the activity of lactate dehydrogenase was increased（P〈0.05）.The pro-apoptotic protein Bim was increased at 8 hours（P〈0.05）.The expression of caspase-3 was obviously increased at immediately after recovery（P〈0.05）.Therefore,hyperthermia induces myocardial cells damage with apoptosis as main types.The pro-apoptotic protein Bim and caspase-3 may play an important role in cardiomyocyte apoptosis induced by hyperthermia.