Abstract:

Background  Eccentric exercise or high tension exercise could cause damage to skeletal muscle structure, resulting in deficiency of dystrophin and secondary loss of dystrophin-glycoprotein complex (DGC) from the sarcolemma, which indicated that down-regulation of dystrophin was one of the key points of skeletal muscle injury from eccentric exercise. Duchenne muscular dystrophy (DMD) is caused by mutations of DMD gene, resulting in the absence of dystrophin, which means that skeletal muscles of DMD patients after birth are in the natural state of actual path of force transmission which carried high tension from eccentric exercise. This paper investigated systematically whether expression of DGC is associated with progressive muscle weakness in natural history of DMD, and analyzed the expression of DGC at the sarcolemma of 197 confirmed DMD cases (9 days-12 years old).  Methods  The expression of α- and β-dystroglycan (DG), α-, β-, γ- and δ-sarcoglycan (SG) and syntrophin at the sarcolemma of DMD patients was analyzed by immunofluorescent staining.  Results  The study showed that there was no relationship between lack of proteins and progressive muscle weakness with increasing age, although expression of α- and β-DG, α-, β-, γ- and δ-SG and syntrophin at the sarcolemma at different stages of 197 DMD patients (9 days-12 years old) had different degrees of deficiency.  Conclusions  Deficiency of DGC may occur before birth and DMD patients were recommended to avoid further damage to skeletal muscles from eccentric exercise and high-resistance movement in activities of daily life and rehabilitation training.

Key words:

摘要：

研究背景 离心运动或高张力运动可以损伤骨骼肌结构，使抗肌萎缩蛋白（dystrophin）缺失，并继发性引起抗肌萎缩蛋白-糖蛋白复合物（DGC）缺乏，表明dystrophin 蛋白表达下降是离心运动对骨骼肌损伤的关键标记之一。DMD 基因突变致dystrophin 蛋白缺失继而导致Duchennne 型肌营养不良症，表明Duchenne 型肌营养不良症患儿自出生起即处于骨骼肌离心运动所承载的高张力力量传递通路的自然状态。本研究探讨Duchenne 型肌营养不良症患儿骨骼肌功能进行性下降与DGC 复合物表达水平之间的关系。方法 共197 例9 天至12 岁Duchennne 型肌营养不良症患儿，采用免疫荧光染色观察肱二头肌肌膜DGC 复合物中的肌营养不良蛋白聚糖（α- 和β-DG），肌聚糖蛋白（α-、β-、γ-和δ-SG），互生蛋白（syntrophin）表达变化。结果 各年龄段Duchenne 型肌营养不良症患儿肌膜α-和β-DG，α-、β-、γ-和δ-SG，syntrophin 蛋白均呈现不同程度缺乏，但与增龄伴随的肌力下降并无关联性。结论 DGC 复合物缺乏可能在出生前即已发生，建议Duchenne 型肌营养不良症患儿在日常生活活动和康复训练中避免离心运动和抗高阻力动作对骨骼肌的进一步损伤。

关键词: 肌营养不良, 杜氏, 肌营养不良蛋白相关蛋白复合物, 运动损伤