Developmental study of the expression of dystrophin in cultured human muscle aneurally and innervated with fetal rat spinal cord.
So far there have been no developmental studies including the influences of innervation and contractile activity on the expression of dystrophin in cultured human muscle. We performed immunocytochemical studies of the localization of dystrophin on aneurally cultured non-contracting (AMs) and innervated continuously contracting cross-striated human muscle fibers (ICMs) with fetal rat spinal cord from normal and Duchenne muscular dystrophy (DMD) biopsied muscles. In normal AMs, myoblasts and some immature AMs showed negative staining of dystrophin, but many AMs had a patchy (discontinuous) distribution of dystrophin in the subplasmalemmal region and with some granularity near the sarcolemma and in the deeper cytoplasm. In normal ICMs, dystrophin was localized continuously at the inner aspect of the sarcolemmal membrane and some periodic dense patterns were detected in some areas. Both AMs and ICMs from DMD had negative staining of dystrophin. To investigate the muscle contractile activity on the distribution of dystrophin, we paralyzed ICMs with tetrodotoxin (TTX) for two weeks from the first appearance of muscle contractions. In paralyzed innervated muscles (PIMs), dystrophin remained in a patchy (discontinuous) pattern at the inner aspect of the plasmalemma similar to that in AMs. It is strongly suggested that muscle contractile activity plays an important role in the continuous and even distribution of dystrophin at the sarcolemma during development.
Park-Matsumoto
Y C
YC
Department of Neurology, School of Medicine, Tokyo Medical and Dental University, Japan.
Kameda
N
N
Kobayashi
T
T
Tsukagoshi
H
H
D000328:Adult; D000818:Animals; D002478:Cells, Cultured; D016189:Dystrophin / Q000032:analysis*; D005314:Embryonic and Fetal Development / Q000502:physiology; D006801:Humans; D007124:Immunoenzyme Techniques; D008854:Microscopy, Electron; D008875:Middle Aged; D009132:Muscles / Q000737:chemistry* / Q000294:innervation; D009136:Muscular Dystrophies / Q000378:metabolism* / Q000503:physiopathology; D051381:Rats; D015222:Sodium Channels / Q000187:drug effects; D013116:Spinal Cord / Q000196:embryology*; D013779:Tetrodotoxin / Q000494:pharmacology
D016189:Dystrophin; D015222:Sodium Channels; D013779:Tetrodotoxin