Regeneration following denervation of minced gastrocnemius muscles in mice

Gastrocnemius muscles in mice were minced and orthotopically implanted. At the same time all nervous supply to this muscle was completely removed. It was observed that initially the pattern of muscle regeneration was similar to what was observed in a normally innervated implant. But by day 6, distinct degeneration of regenerated muscle fibres sets in, which continues unabated so that by about 3 weeks there usually remains only a thin band of connective tissue in place of the implant. Histochemically, there is a gradual loss of SDH, myofibrillar ATPase and cholinesterase activities within the degenerating muscle fibres and a corresponding appearance of these enzymes in the regenerating fibres. In the denervated implants, with the onset of degeneration of the regenerating fibres, the enzymatic activities were also lost. Histochemical fibre typing was not achieved within the regenerating fibres. The regeneration and degeneration pattern of the denervated muscle observed in the present study is compared with the one observed in other animals.