Direct muscle neurotization in rat soleus muscle.

The authors carried out an experimental study using rat soleus muscles to evaluate reinnervation of the denervated muscles by direct muscle neurotization. They also attempted to determine whether there is any difference in the regeneration process between original (tibial) and foreign (peroneal) nerve neurotization. For functional evaluation, they did an electrophysiologic study by analyzing pattern, latency, amplitude, and duration of compound motor action potential. For histochemical studies, both hematoxyline-eosin stain and nicotineamide adenin dehydrogenase stainings were used to identify the morphology and the change of the type of muscle fiber. Combined silver-acetylcholinesterase stain was performed to identify reinnervated motor endplate and axonal sprouting. They confirmed evidence of regeneration of the denervated muscle by direct muscle neurotization. Regenerating muscles showed type groupings of muscle fibers. The newly-formed ectopic motor endplate was connected with axonal sprouting. The giant motor endplate composed of mature axon sprouting and several new ectopic motor endplates, appeared in the neurotization group. There was no significant difference in the regeneration process between original and foreign nerve neurotization.