Calpain抑制剂降低高糖诱导的心肌细胞凋亡的机制

Mechanism of calpain inhibitor on cardiomyocyte apoptosis induced by high glucose

目的:探讨calpain抑制剂降低高糖诱导的心肌细胞凋亡的机制。方法:分离培养SD乳鼠心肌细胞,实验分为3组:对照组、高糖组(35mmol/L)、高糖(35mmol/L)+calpain抑制剂(ALLN)(25mmol/L)组。MTT测定各组心肌细胞的生长活力,激光共聚焦显微镜观察和检测心肌细胞线粒体通透性和膜电位,Westernblot法检测激活型半胱天冬酶(caspase)-3蛋白的表达。结果:高糖组心肌细胞生存率为(55±11)%;高糖+ALLN组心肌细胞生存率为(70±15)%,2组比较差异有统计学意义(P<0.05)。高糖可以刺激心肌细胞线粒体通透性增加,线粒体膜通道孔开放,而ALLN预处理可以抑制高糖对心肌细胞的这种作用[相对荧光强度:(30±15)%∶(60±11)%,P<0.05]。高糖可以降低心肌细胞线粒体膜电位,而ALLN预处理可以抑制高糖对心肌细胞的这种作用[相对荧光强度:(22±12)%∶(80±19)%,P<0.05]。高糖刺激可以导致心肌细胞激活型caspase-3的表达增加,而加入ALLN预处理后可以抑制激活型caspase-3的表达,2组比较差异有统计学意义[(0.42±0.11)∶(0.21±0.12),P<0.05]。结论:Calpain抑制剂有降低高糖诱导的心肌细胞凋亡的保护效应,其机制可能涉及多方面。

Objective：To investigate the mechanism of calpain inhibitor on cardiomyocyte apoptosis induced by high glucose in cultured rat.Method：Cardiomyocytes were randomly divided into three groups： the control group,the high glucose group and the calpain inhibitor（ALLN） group.MTT assay was carried out to detect the viability of cultured cardiomyocytes,and laser confocal microscopy was used to observe the mitochondrial permeable transition and membrane potential.The change of caspase-3 activity in cardiomyocyte was detected by Western blot.Result：The viability of cardiomyocyte was（55±11）% in the high glucose group,and（70±15）% in ALLN group（P〈0.05）.After hyperglycemia,the mitochondrial permeable transition of cardiomyocyte was increased [（30±15）% vs（60±11）%,P〈0.05] and membrane potential [（22±12）% vs（80±19）%,P〈0.05] was declined.However,the effects cloud be inhibited by pretreatment of ALLN.Hyperglycemia could increase the expression of cleaved caspase-3,while the expression of cleaved caspase-3 was down-regulated with pretreatment of ALLN [（0.42±0.11） vs（0.21±0.12）,P〈0.05].Conclusion：Calpain inhibitor can protect cardiomyocyte from apoptosis under the high glucose condition.