Regeneration of muscles after cardiotoxin injury. I. Cytological aspects.

Regeneration of several adult rat and mouse skeletal muscles was studied after degeneration of muscle fibers had been obtained by the selective action of the cardiotoxin of Naja mossambica mossambica venom. Experimental conditions were set up to ensure minimal damage to satellite cells and also the nerves and blood vessels of the original muscles. As in the other types of experimental regeneration, the structure of the regenerated muscle appeared in many respects different from that of the normal muscle. Moreover the neuromuscular junctions of 'en plaque' type were transformed to 'en grappe' type junctions. Many ultrastructural abnormalities often displayed by these junctions might be linked, at least partially, to the persistence in the regenerating muscle of the original synaptic basal lamina sheaths and their inductive properties.