Capacity of foetal spinal cord obtained from dystrophic mice (dy²J) to promote muscle regeneration

Abstract

RECENTLY Gallup and Dubowitz¹ described a series of tissue culture experiments in which they attempted to clarify the part played by the motor neurone in the pathogenesis of murine muscular dystrophy. Bishop et al.² had shown that muscle explants obtained from human subjects grew normally in Garell flasks. Gallup et al.³ reported similar results with muscle explants of trypsinised minced muscle obtained from dystrophic chick that had been grown in vitro on collagen-coated surfaces in Petri dishes. They were unable to differentiate between cultured normal and dysitrophic muscle. But they reported significant differences between cultures of normal mouse cord with either normal or dystrophic muscle and dystrophic cord with either normal or dysitrophic muscle. When contacted by ventral root neurites from normal spinal cord, the muscle cells of both normal and dystrophic muscle fused to form new fibres with well developed cross striations and peripherally located nuclei. The appearance of both normal and dystrophic muscle coupled with ‘dystrophic’ spinal cord was quite different. The initial cellular regenerative response was followed in most cases by degeneration and disappearance of all muscle elements, leaving only strands of connective tissue. In only three out of thirteen cultures were myotubes formed, and these failed to develop synchronised contractions.