高血糖致骨骼肌细胞凋亡机制及α-硫辛酸保护作用的实验研究

目的 探讨高血糖导致骨骼肌细胞凋亡的机制以及抗氧化剂α-硫辛酸的保护作用.方法 将30只雄性Wistar大鼠完全随机分为正常对照组(10只)、糖尿病组(8只)和α-硫辛酸组(8只),对后2组大鼠采用一次性尾静脉注射链脲佐菌素(STZ)45 mg/kg体重制备糖尿病大鼠模型,正常对照组尾静脉注射柠檬酸钠缓冲液,α-硫辛酸组大鼠每天腹腔注射α-硫辛酸0.033 ml/g,糖尿病组注射0.3ml的缓冲液,于α-硫辛酸注射后12周处死动物,处死前测量体重、血糖,苏木素-伊红染色和Masson染色观察骨骼肌的结构和纤维化,测定线粒体内外的细胞色素C、骨骼肌组织的天冬氨酸半胱氨酸(Caspase)-3.结果 糖尿病组骨骼肌纤维化明显增加,胶原含量明显高于正常对照组(11.73±1.12)%比(3.12±0.32)%,P＜0.01],α-硫辛酸组胶原含量(6.58±0.65)%明显低于糖尿病组(1.73±1.12)%](P＜0.05).与对照组比较,12周时糖尿病大鼠骨骼肌出现了明显的结构紊乱和纤维化,Caspase-3的蛋白质水平明显增加,线粒体内的细胞色素C减低,线粒体外的细胞色素C增加;α-硫辛酸治疗12周可以明显改善骨骼肌结构,减少纤维化,减少线粒体细胞色素C的释放,降低Caspase-3的蛋白质的表达,差异有统计学意义.结论 高血糖通过增加线粒体细胞色素C的释放导致骨骼肌细胞凋亡,α-硫辛酸通过减少线粒体细胞色素C的释放减少骨骼肌的细胞凋亡,防护糖尿病骨骼肌病变.

Protective effects of alpha lipoic acid on diabetic skeletal myopathy by attenuation mitochondria-dependent cell apoptosis

Objectives To explore the mechanisms of high glucose induced skeletal muscle cell apoptosis and observe the protection of antioxidant-lipoic acid(α-LA) on skeletal muscle. Methods Diabetic rat model was induced by a single dose of streptozotocin (45 mg/kg), randomly divided into 3 groups: normal control, diabetes control and α-LA. The structure and fibrosis of skeletal muscle were determined by HE and masson staining respectively. The protein level of cytochrome-c and Caspase-3 were detected by western blot. Results Twelve weeks after STZ-injection, there were significantly structural abnormalities and increased fibrosis in diabetic skeletal muscle,Caspase-3 protein level and mitochondrial cytochrome c release significantly increased in DM group versus control group. However, these diabetes-related skeletal dysfunctions were significantly ameliorated by antioxidant α-LA administration. Conclusions Our findings indicate that high glucose can increase mitochondrial cytochrome c release resulting in skeletal Apoptosis. The antioxidant-LA can effectively attenuate mitochondria-dependent skeletal apoptosis and exert a protective role against the development of diabetic skeletal myopathy.