Expression of desmin in normal and laser (HeNe) irradiated regenerating skeletal muscles in the toad (Bufo viridis) and the white rat

The expression of desmin was investigated using immunohistochemical methods in normal and low-energy laser (HeNe) irradiated regenerating rat and toad gastrocnemius muscles following partial excision in the former and cold injury in the latter. During the initial stages of regeneration, presumptive myoblasts immunoreacted to desmin antibodies while other mononucleated cells remained unstained. At a later stage the cytoplasm of the myotubes was intensely stained with anti-desmin. At all time intervals there were more mature myogenic structures in the injured zones of the laser irradiated rat or toad muscles than non-irradiated muscles as indicated by the positive immunoreactivity to desmin. It is concluded that desmin immunostaining provides additional information on the role of histological structures during the regeneration process. The process of skeletal muscle regeneration follwing injury is markedly promoted by low-energy direct laser irradiation during the regeneration process. The results also indicate that the rate of differentiation of myoblasts from undifferentiated stem cells is enhanced by the laser irradiation.