Absence of exogenous satellite cell contribution to regeneration of frozen skeletal muscle.

Rat extensor digitorum longus (EDL) muscles were repeatedly frozen and thawed to kill completely all cellular constituents. Within four days, blood vessels and phagocytic cells invaded the muscle. Migrating or circulating myoblasts were not among the invading cells, and could be induced to invade the frozen muscle only when a physical bridge was created with an adjacent intact muscle. A further requirement for migration was that the connective tissue investments of both the frozen EDL and adjacent muscle had to be disrupted. This study demonstrates that regeneration of a muscle is primarily dependent upon the intrinsic satellite cell population, although under some circumstances recruitment of extrinsic cells is possible.