Three-dimensional cytoarchitecture of complex branched fibers in soleus muscle from mdx mutant mice

Authors

  • Tetsuro Tamaki PhD,

    Corresponding author
    1. Division of Human Structure and Function, Department of Physiology, Tokai University School of Medicine, Bohseidai, Isehara, Kanagawa, 259-11 Japan
    • Department of Physiology, Division of Human Structure and Function, Tokai University School of Medicine, Bohseidai, Isehara, Kanagawa 259-11 Japan
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  • Tadashi Sekine,

    1. Division of Electron Microscopy Laboratory, Tokai University School of Medicine, Bohseidai, Isehara, Kanagawa, 259-11 Japan
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  • Akira Akatsuka,

    1. Division of Electron Microscopy Laboratory, Tokai University School of Medicine, Bohseidai, Isehara, Kanagawa, 259-11 Japan
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  • Shuichi Uchiyama,

    1. Division of Human Structure and Function, Department of Physiology, Tokai University School of Medicine, Bohseidai, Isehara, Kanagawa, 259-11 Japan
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  • Shoichi Nakano

    1. Division of Human Structure and Function, Department of Physiology, Tokai University School of Medicine, Bohseidai, Isehara, Kanagawa, 259-11 Japan
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Abstract

Three-dimensional cytoarchitecture and types and features of muscle fibers were examined in soleus muscles from mdx mutant mice at different stages of development. In the 2-week-old mice, no abnormal muscle fibers were observed light microscopically, whereas in the 4-week-old animals, disrupted fibers were frequent in light microscopy and scanning electron microscopy. Muscle fibers fused with several short fiber branches appeared at the sixth week after birth and increased in number until the tenth week. In the 1-year-old mice, approximately ten or more muscle fibers were seen fused together. They had many complex branches forming an “anastomosing syncytial reticulum.” Muscle fibers with irregular diameters and aggregations of the same type fibers were also observed.

Our results demonstrated that these complex branched fibers might be formed by long term repetition of the degeneration and regeneration cycle during the development of soleus muscles, indicating that the characteristic features of muscle fibers with irregular diameters and aggregations of the same type fibers are certainly dependent on the existence of the complex branched fibers. © 1993 Wiley-Liss, Inc.

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