Relationship between the tissue and epimorphic regeneration of muscles

Abstract

Entire muscles in vertebrate extremities can regenerate from minced muscle fragments implanted into the bed of the removed muscle. The histological course of regeneration of muscle fibers in this system is the same as that described in damaged mammalian muscle. This type of regeneration has been called the tissue regeneration of muscle, and entire muscles have been regenerated by this mode in urodelan and anuran amphibians, birds, and mammals. Entire muscles are also formed in a regenerating limb (an epimorphic regenerative process). It is postulated that there are two fundamentally different modes of regeneration of muscles. Epimorphic regeneration is relatively slow, and the blastema seems to play an important role. The end product is morphologically and functionally perfect. Morphogenesis seems to be controlled in a manner analogous to that in the embryonic limb. The tissue regeneration of muscles is rapid, occurring without the mediation of a blastema. The end product is smaller and less well organized than a normal muscle, and its morphogenesis seems to require the function of the limb. A possible parallel reaction of skeletal elements is discussed. © 1970 by the American Society of Zoologists.