Comparison of neuromuscular junction of two kinds of mouse models of Duchenne muscular dystrophy

Kong Jie; Cao Ji-qing; Yang Juan; Chen Fei; Li Ya-qin; Zhang Cheng

doi:10.3969/j.issn.2095-4344.2016.05.009

Abstract：BACKGROUND:Neuromuscular junction structure has defects in patients with Duchenne muscular dystrophy, mainly presenting acetylcholine receptor structure fragmentation and the reduction of spine-like processes on thepostsynaptic membrane. It is generaly recognized that the structural defects are induced by structural damage of muscle cels and muscle fiber necrosis. OBJECTIVE:To explore the reasons of damage on neuromuscular junction in mouse models of Duchenne muscular dystrophy. METHODS: We introduced Duchenne muscular dystrophy models of male mdx mice and male Dko mice. After gene identification, they were used for tests. Male C57BL/6 mice were selected as normla controls. Hematoxylin-eosin staining was utilized to detect pathological changes in muscles. Neuromuscular junction structure was revealed using immunofluorescence staining. The differences in dystrophin expression, pathological features and neuromuscular junction structure were compared in mouse models of two kinds of Duchenne muscular dystrophy. RESULTS AND CONCLUSION:The introduced mouse models were accorded with the requirement of our experiment in aspects of genotype and protein expression levels. The number of acetylcholine receptor was apparently reduced in the neuromuscular junction of two kinds of mouse models. Although dko mouse muscles presented more obvious inflammatory infiltration and muscle fiber damage compared with mdx mice, but there was no significant difference in the damage to neuromuscular junction between them, and acetylcholine receptor fragmentation was identical. The evidence suggested that structural damage of neuromuscular junction and inflammatory pathological response are independent events. There is no direct relationship between them. Dystrophin gene deficiency is the main cause of the fragmentation of the acetylcholine receptor.