Objective To explore the role of potassium channel in cardiomyocyte apoptosis induced by ischemia/reperfusion process. Methods Cell viability,caspase-3 activity,intracellular reactive oxygen species(ROS)levels and cell membrane integrity were observed in apoptotic model of mouse cardiomyocytes induced by ischemia/reperfusion(I/R).Experiment groups included negative control,positive control(I/R)and drug treatment group(I/R + potassium channel blocker).Results (1)Potassium channel blockers potently inhibited cardiomyocyte apoptosis induced by I/R.Cell viability in Quinine(81.1%)and BaCl2(82.3%)groups were higher than in positive group (52.1%)(all P＜0.01).(2)Compared with positive control group(482.3%),potassium channel blockers(188.3% in Quinine group and 191.4% in BaCl2 group)inhibited caspase-3 activity significantly 24 hours after reperfusion(P＜0.01).(3)In both positive control and drug groups,the cell lactate dehydrogenase(LDH)leakage was less than 10% at 96 hours after reperfusion.Conclusions Potassium channel blockers can protect injured cardiomyocyte by inhibiting caspase-3 activity and ROS production in I/R process.%目的 探讨钾离子通道在缺血再灌注(I/R)诱导心肌细胞凋亡过程中的作用.方法 在原代培养鼠心肌细胞I/R损伤诱导心肌细胞凋亡模型中,观察钾离子通道阻断剂奎宁和氯化钡对心肌细胞的存活率、半胱天门冬氨酸酶(caspase)-3活性、活性氧的活性水平和细胞膜完整性的影响.实验分为4组:(1)阴性对照组;(2)I/R阳性对照组;(3)I/R奎宁干预组;(4)I/R氯化钡干预组.结果 (1)钾离子通道阻断剂能有效抑制I/R诱导的心肌细胞凋亡,奎宁和氯化钡组细胞的成活率分别是81.1%和82.3%,与阳性对照组(52.1%)比较,差异有统计学意义(均为P＜0.01);(2)钾离子通道阻断剂能有效的抑制caspase-3活性的激活,I/R 24 h后细胞的caspase-3活性奎宁和氯化钡组分别是188.3%和191.4%,与阳性对照组(482.3%)比较,差异有统计学意义(P＜0.01);(3)钾离子通道阻断剂能有效的抑制活性氧产生,I/R 24 h后奎宁和氯化钡组在细胞内的相对活性氧活性水平分别是21.6和19.1,与阳性对照组61.4比较,活性氧活性水平降低(P＜0.01);(4)细胞膜完整性实验乳酸脱氢酶水平显示,各组I/R 96 h后细胞坏死低于10.0%.结论 在I/R诱导的心肌细胞凋亡模型中,钾离子通道阻断剂通过抑制caspase-3活性、活性氧产生介导保护心肌细胞凋亡的发生.
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