Regenerated EDL muscle of rats requires innervation to maintain AChE molecular forms

Extensores digitorum longi of rats, infarcted and denervated by different surgical procedures, were used to analyze by biochemical and cytochemical methods the acetylcholinesterase (AChE) changes during muscle degeneration, regeneration, and early or delayed reinnervation. Biochemical tests showed that the regenerating muscle produces globular AChE forms (36% of controls) and small amounts of A12 (16S) asymmetric form (5% of controls); at the end of the regeneration, innervation and electromechanical function are required for the complete recovery of globular forms, and are absolutely critical to prevent A12 (16S) disappearance. Cytochemical observations showed that, unlike nicotinic receptor, AChE deposited at the neuromuscular junction before ischemic necrosis is protected from breakdown, as is the basal lamina of muscle fibers. Taken together, these observations contribute to the understanding of the factors that play a critical role in muscle repair and are, therefore, of clinical relevance.