Gold tracer studies of muscle regeneration.

Rabbits were injected with soluble gold, and cold injury was inflicted upon their extraocular muscles. Following the typical freeze-thaw damage in which the myofiber basement membrane is preserved, a polymorphonuclear granulocyte exudation occurred. At this stage only a few interstitial cells with long processes contained gold. At one and two days abundant mononuclear cells with gold were observed at the site of injury. In subsequent stages of muscle regeneration the amount of tracer decreased but myoblasts, and even fully formed myotubes, often contained detectable gold. Some data on "in vivo" gold salt kinetics and the specificity of gold localization were utilised in the study of the relation between mononuclear interstitial cells and myoblasts.