Shibuya S, Wakayama Y
Department of Medicine, Showa University Fujigaoka Hospital, Yokohama, Japan.
Neuropathol Appl Neurobiol. 1991 Aug;17(4):335-44. doi: 10.1111/j.1365-2990.1991.tb00730.x.
The structure of the muscle plasma membrane of tibialis anterior muscles of X chromosome-linked muscular dystrophy (mdx) mice was studied by the freeze-fracture technique at 3, 7 and 14 days after birth. The ultrastructural features of the freeze-fracture replicas of the muscle plasma membrane alterations in young mdx mice showed a decrease of orthogonal array, orthogonal array subunit particle and intramembranous particle densities on the protoplasmic face. The results are consistent with the previous studies which have shown that the orthogonal arrays are significantly decreased in number in muscle plasma membranes of adult mdx mice and in those of Duchenne dystrophy. However, the immature mdx mouse membranes at 3 days after birth contained as many orthogonal arrays as controls and did not show a statistically significant decrease (P greater than 0.1 by the Wilcoxon rank-sum test). Moreover, the orthogonal arrays were also numerous in young mdx mouse muscle plasma membranes at 7 and 14 days after birth, although the density was less than that of the control mice (P less than 0.01 by the Wilcoxon rank-sum test). These changes in young mdx mouse plasma membranes may precede the later muscle fibre degeneration in this mouse dystrophy and may provide us with an additional clue to the mechanism why mdx mice scarcely show any disability despite the absence of dystrophyn.
采用冷冻蚀刻技术，对出生后3天、7天和14天的X染色体连锁型肌营养不良（mdx）小鼠胫骨前肌的肌质膜结构进行了研究。幼年mdx小鼠肌质膜改变的冷冻蚀刻复制品的超微结构特征显示，原生质面上正交阵列、正交阵列亚基颗粒和膜内颗粒密度降低。这些结果与先前的研究一致，先前的研究表明，成年mdx小鼠和杜氏肌营养不良患者的肌质膜中正交阵列的数量显著减少。然而，出生后3天的未成熟mdx小鼠膜中的正交阵列数量与对照组一样多，且未显示出统计学上的显著减少（Wilcoxon秩和检验，P大于0.1）。此外，出生后7天和14天的幼年mdx小鼠肌质膜中的正交阵列也很多，尽管其密度低于对照小鼠（Wilcoxon秩和检验，P小于0.01）。幼年mdx小鼠质膜的这些变化可能先于该小鼠肌营养不良后期的肌纤维变性，并可能为我们提供额外线索，以解释mdx小鼠尽管缺乏肌营养不良蛋白却几乎不表现出任何残疾的机制。
