Recovery of free muscle grafts in rat: improvement is associated with an increase in cyclic adenosine monophosphate concentration or use of the condition/test paradigm.
The muscle fibers in freely grafted skeletal muscles degenerate and are replaced by new fibers which develop within the graft. Myogenesis in regenerating muscle recapitulates, to a large extent, developmental myogenesis and may depend on similar modulating influences. In addition to the generation of new fibers, functional recovery of free muscle grafts also requires reinnervation and revascularization of the new fibers. Recovery of function should be improved by enhancing either myogenesis or reinnervation and revascularization. We have used two procedures, shown previously to stimulate peripheral nerve regeneration, to improve the morphologic and functional recovery of free, orthotopic grafts of rat extensor digitorum longus muscle. Each of the procedures was effective, but had potentially different sites of action. The first procedure, the condition/test paradigm, presumably increases the rate and extent of graft reinnervation. The second procedure, continuous infusion of the adenylate cyclase activator forskolin during the first 21 days after grafting, may influence both myogenesis and nerve regeneration. Each procedure increased regenerating muscle fiber size and functional capacity, and forskolin also significantly increased capillary density and fatigue resistance.
D000818:Animals; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000032:analysis / Q000502:physiology*; D005260:Female; D009119:Muscle Contraction; D009132:Muscles / Q000032:analysis / Q000098:blood supply / Q000187:drug effects / Q000502:physiology / Q000637:transplantation*; D009389:Neovascularization, Pathologic; D051381:Rats; D011919:Rats, Inbred Strains
D005576:Colforsin; D000242:Cyclic AMP