钙激活蛋白酶抑制剂对高糖诱导乳鼠心肌细胞凋亡的作用机制

Effect of calpain inhibitor on hyperglycemia-induced apoptosis in cultured rat cardiomyocyte

目的探讨钙激活蛋白酶（Calpain）抑制剂对高糖诱导的乳鼠心肌细胞凋亡的作用机制。方法分离培养SD乳鼠心肌细胞，实验分为3组：（1）对照组；（2）高糖（35mmol／L）组，刺激72h；（3）高糖（35mmol／L）＋Au州（25mol／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caspase-3蛋白的表达。结果MTr结果分析显示高糖刺激72h后，心肌细胞生存率下降（55％±11％），ALLN预处理组生存率为（70％±15％），与高糖组比较差异具有统计学意义（P〈0．05）。高糖可以刺激心肌细胞线粒体通透性增加，mPTP孔开放，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：30％±15％vs60％±11％，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，加入ALLN预处理后可以抑制激活型caspase-3的表达，差异有统计学意义（0．42±0．11VS0．21±0．12，P〈0．05）。结论Calpain抑制剂对高糖诱导的乳鼠心肌细胞凋亡的作用存在保护效应。

Objective To investigate the mechanism of inhibitor of calpain on hyperglycemia-in- duced apoptosis in cultured rat cardiomyocyte. Methods Cardiomyocytes were randomly divided into three groups （control, high glucose, and ALLN）. MTT assay was used to detect the viability of cultured cardio- myocytes. Laser confocal microscopy was used to observe the mitochondrial permeable transition and mem- brane potential. The change of Caspase-3 activity in cardiomyocytes was detected by western blot. ResUlts MTT assay showed that, after 72 h of hyperglycemia, the viability of cardiomyocytes was significantly de- clined （55% ± 11%）, and the viability in the ALLN pretreatment group was （70% ± 15%） （ P 〈 0. 05）. After hyperglycemia, the mitochondrial permeable transition of cardiomyocyte was increased（30% ± 15% vs 60% ± 11% , P 〈0. 05）, and membrane potential was declined. Hyperglycemia could increase the expression of cleaved capsase-3, while with pretreatment of ALLN the expression of cleaved caspase-3 was downregulation（0.42 ±0. 11 vs 0.21 ±0. 12, P 〈0.05）. Conclusions The calpain inhibitor can protect cardiomyocytes from apoptosis under the high glucose condition.