【摘要】 目的:探讨线粒体ATP敏感性钾离子通道(mitoKATP)开放剂二氮嗪(DE)对离体大鼠供心不同时程冷保存时促凋亡蛋白Smac/DIABLO表达的影响及机制。方法:SD大鼠随机分为3组,包括空白对照组、单纯冷保存组、DE组(Celsior保存液中含30μmol/L DE),后2组又按冷保存时程不同,分别分为3、6、9、12 h组。实验结束后采用原位末端标记染色法(TUNEL)检测心肌细胞凋亡,采用Western blotting法检测心肌组织中caspase-3蛋白及胞浆Smac/DIABLO蛋白表达。结果:(1)在Celsior保存液中加入DE后,心肌细胞凋亡指数及caspase-3蛋白表达显著低于相应单纯冷保存组。(2)DE可使Smac/DIABLO蛋白表达高峰由冷保存6 h延迟至9 h。(3)DE的上述作用可被mitoKATP通道特异性阻断剂5-羟基葵酸盐(5-HD)所取消。结论:DE具有对抗冷保存诱导心肌细胞凋亡的作用,这种保护作用可能与其激活mitoKATP通道和减少促凋亡蛋白Smac/DIABLO表达有关。更多还原

【Abstract】 AIM: To investigate the effect of a mitochondrial ATP-sensitive potassium channel(mitoKATP) opener diazoxide(DE) on Smac/DIABLO protein expressions in rat heart suffered from different duration of hypothermic preservation.METHODS: The Langendorff model of isolated rat heart was used.After stored in 4 ℃ Celsior solution with or without DE(30 μmol/L) for different time(0,3,6,9 or 12 h).Cell apoptosis was detected by TUNEL technique.The expression of Smac/DIABLO protein in cytoplasm and total caspase-3 protein in myocardia tissue was also analyzed by Western blotting.RESULTS:(1) Compared to the hypothermic preservation groups,DE reduced the percentage of apoptotic cells and the expression of caspase-3 protein in myocardia tissue.(2) The peak of Smac/DIABLO protein expression level appeared at 6 h after hypothermic preservation,and which was postponed to 9 h by DE.(3) The above effects of DE were attenuated by a mitoKATP channel inhibitor 5-hydroxydecanoate(5-HD).CONCLUSION: The findings indicate that in the isolated rat heart,DE protects myocardium against different duration of hypothermic preservation injury via opening of mitoKATP channel and inhibition of Smac/DIABLO protein expression.更多还原