自噬在Duchenne型肌营养不良中的研究

Role of autophagy in Duchenne muscular dystrophy

摘要:

目的 检测Duchenne型肌营养不良症（DMD）患者骨骼肌中LC3和p62的表达情况，分析自噬在DMD骨骼肌细胞坏死中的作用。方法 收集2008年1月~2015年5月在我院就诊的病理确诊为DMD的患者（DMD组，81例），另以怀疑为肌病，但肌肉病理未见明显病变者为对照组（6例）。所有入选者均行心肌酶学、肌电图、骨骼肌活检常规组织学和酶学染色、抗dystrophin-N，-C，-R和抗dysferlin免疫组织化学染色。检测其中6例DMD患者及对照组骨骼肌中LC3和p62的表达。结果 81例DMD患者均为男性，起病年龄（4.60±2.35）岁，首发症状多以双下肢起病为主。血清肌酸激酶值的高峰出现在患者年龄的6~8岁，随着肌细胞明显坏死，肌酸激酶水平下降，但仍高于正常。在DMD患者骨骼肌中，组织病理均示典型肌营养不良改变。半定量Western blot提示DMD患者骨骼肌中LC3-Ⅱ的表达降低，而p62表达显著升高。结论 自噬功能障碍可能参与了DMD骨骼肌细胞坏死的病理生理过程。

Abstract:

Objective To investigate the expression of microtubule-associated protein I light chain 3 (LC3) and p62 in skeletal muscle in patients with Duchenne muscular dystrophy (DMD) and the role of autophagy in necrosis of skeletal muscle cells.Methods A total of 81 patients with pathologically confirmed DMD who visited our hospital from January 2008 to May 2015 were enrolled as DMD group, and 6 patients who were suspected of myopathy and had no marked muscle lesions were enrolled as control group. Myocardial enzyme examination, electromyography, histological and enzymatic staining in skeletal muscle biopsy, and anti-dystrophin-N,-C,-R and anti-dysferlin immunohistochemical staining were performed for all subjects. The expression of LC3 and p62 in skeletal muscle was measured for 6 DMD patients and the control group.Results All of the 81 DMD patients were male with a mean onset age of 4.60±2.35 years, and the initial symptom was mainly muscle weakness in the lower limbs. Serum creatine kinase reached a peak level at an age of 6~8 years and then gradually decreased with increased necrosis of myocytes. Histopathological examination showed typical muscular dystrophy in skeletal muscle in DMD patients. Semi-quantitative Western blot showed a reduction in the expression of LC3-Ⅱ and an increase in the expression of p62 in skeletal muscle in DMD patients.Conclusions Autophagy dysfunction may be involved in the pathophysiological process of skeletal muscle cell necrosis in DMD.