No change in skeletal muscle satellite cells in young and aging rat soleus muscle

Satellite cells are muscle stem cells capable of replenishing or increasing myonuclear number. It is postulated that a reduction in satellite cells may contribute to age-related sarcopenia. Studies investigating an age-related decline in satellite cells have produced equivocal results. This study compared the satellite cell content of young and aging soleus muscle in rat, using four different methods: dystrophin-laminin immunohistochemistry, MyoD immunohistochemistry, electron microscopy, and light microscopy of semi-thin sections. The absolute quantity of satellite cells increase with age, but satellite cell percentages were similar in young and aging soleus muscles. There were no differences in satellite cell quantity among MyoD immunohistochemistry, electron microscopy, and semi-thin sections. All three methods had significantly more satellite cells than with dystrophin-laminin immunohistochemistry. We conclude that satellite cell number does not decrease with age and postulate that satellite cell functionality may be responsible for age-related sarcopenia.