Use of antibodies to identify satellite cells with a light microscope.

Satellite cells are essential for the growth and regeneration of skeletal muscles but the study of them has been difficult due to the need to use an electron microscope. This article describes a method which enables satellite cells to be identified with a light microscope. Satellite cells were distinguished from: (1) myonuclei on the basis of whether the nuclei were inside or outside the plasmalemma of a fiber (stained with antidystrophin); and (2) interstitial cells depending on whether they were inside or outside of a fiber's basal lamina (stained with anticollagen IV). Some satellite cells were stained by the antidystrophin which further aided their identification. The question of whether all satellite cells are myogenic has been investigated and discussed. This method will facilitate the study of satellite cells in biopsies of human muscles and the estimation of satellite cell number in laboratory animals.