Atypical myogenesis in hamster hereditary polymyopathy. An in vitro study.

An in vitro study of dissociated muscle cells from normal and myopathic neonatal hamsters was undertaken in an attempt to characterize, by morphological means, a possible abnormal myogenesis in the hereditary polymyopathy of the hamster. There were fundamental structural differences between mononucleated muscle cells before and during myogenic cell fusion, as well as between multinucleated myotubes of normal and myopathic cultures. With reference to conventional morphologic features of normal muscle cultures, more numerous "atypical" foci of myogenesis, some with a bizarre appearance, were seen in myopathic hamsters, as compared to the controls. Because the cultured cells developed in the absence of vascular and neurogenic influences, a myogenic origin may be inferred for the different structural base found in vitro in the myopathic hamster.