Effect of heat stress soon after muscle injury on the expression of MyoD and myogenin during regeneration process.

Heat stress could promote skeletal muscle regeneration. But, in the regeneration process, effects of heat stress on myogenic cells and the regulating factors is unknown. Therefore, Influences of heat stress soon after injury on distribution of the myogenic cells and chronological changes in expression of MyoD and myogenin were examined. The first peak of MyoD expression was temporally correlated with the time when proliferating satellite cells began to appear, and the rapid decline of the MyoD expression from the first peak, with the appearance time of myoblasts, respectively in both the non-Heat and Heat groups. The first peak of myogenin expression was temporally correlated with the time when multinuclear cells began to form in the both groups. Due to the heat stress, proliferation and differentiation of myogenic cells and chronological changes in these factors were accelerated one day earlier than in the non-Heat group. As MyoD and myogenin are regulating factor of proliferation and differentiation, heat stress soon after the muscle injury could accelerate the proliferation and differentiation of myogenic cells and the expression of their regulating factors MyoD and myogenin.