Experimental skeletal muscle grafts as a model of regeneration

It is now well established that mature skeletal muscle has the ability to regenerate, and reports on this phenomenon have existed in the research literature for some 40 years. However, it is only relatively recently, largely due to the advances in microsurgery, that practising surgeons can make direct use of the regenerative ability of skeletal muscle.

Most of the key data on skeletal muscle regeneration have come from experimental studies on muscle grafts in small animal models. One such model is the transplantation of the extensor digitorum muscle of the mouse or rat into the contralateral site, or the relocation of this muscle onto the surface of the tibialis anterior muscle. These and other models, together with the important cellular mechanisms involved in the regeneration of skeletal muscle, are reviewed briefly in this article.

Skeletal muscle cells regenerate rapidly in muscle grafts, arising from satellite cells in the surviving peripheral fibres of the graft within 2 days after grafting. The resultant myoblasts progress towards the necrotic graft centre and occupy the area by 5 days. Revascularization commences at 3 days after grafting, but reinnervation takes many weeks to complete.

With the established knowledge on skeletal muscle regeneration, largely gained from experimental studies of muscle grafts; an understanding of these mechanisms should now be fundamental knowledge for today's practising surgeons.