Effects of endurance exercise and estrogen supplementation on the proliferation of satellite cells

Animal and human studies indicated that overtension and stress release inflammatory substances and growth factors that are produced following exercise, which leads to satellite cell activation and proliferation. The aim of the present study was to investigate the effect of an 8-week endurance exercise and estrogen supplementation on the proliferation of satellite cells in rats. Seventy-six rats were selected and randomly divided into two equal groups, ovariectomized and intact groups. Both groups were randomly divided into four subgroups as follows: endurance exercise, estrogen supplementation, estrogen supplementation with endurance exercise, and control. Then, the endurance exercise group and estrogen supplementation with endurance exercise group performed endurance exercise for 8 weeks, three sessions per week. In each week, the estrogen supplementation group and estrogen supplementation with endurance exercise group were injected subcutaneously with 3 mg/kg of estradiol benzoate. The soleus muscle was retracted and placed into 10 % buffered formalin solution. In a pathological lab, the number of satellite cells was counted and recorded using a light microscope through hematoxylin and eosin staining and immunohistochemistry for CD56. Increase in satellite cell number was significant in the two groups of intact rats treated with estrogen supplementation and the ovariectomized rats which performed endurance exercise. The comparison of these groups' means demonstrated that the satellite cell number increased more in the ovariectomized rats. Endurance exercise and estrogen supplementation can increase the proliferation of satellite cells in the rat's soleus muscle. © 2013, Springer-Verlag London.