[Effect of endurance running training on the structural and metabolic properties of partially denervated soleus muscle in rats].

To estimate the influence of partial denervation on the skeletal muscle, a histochemical and biochemical study was performed on the soleus muscle. Partial denervation was carried out by cutting the proximal root of the nerve innervating the soleus muscle. Further, the effect of endurance running training on the recovery of the partially denervated muscle was examined. Partial denervation did not cause apparent diminution of the number of muscle fibers, nor the muscle weight. Four weeks after denervation, histological changes such as grouping atrophy, fiber splittings, and invasive phagocytes were observed in the denervated portion of the muscle. In the non-running group, mean cross-sectional fiber area of each muscle fiber type increased significantly at 4 weeks after denervation. On the other hand, mean cross sectional fiber area of type II fibers increased at 8 weeks after denervation in the running group. The oxidative enzyme activities were significantly increased in the partially denervated muscle by endurance running training after 4 weeks of denervation. The results indicate that the influence of partial denervation gradually extends over the whole muscle. Furthermore, the running exercise appears to add a good effect to a recovery of the function and the maintenance of muscle structures.