Evidence for a regenerative capacity in adult mammalian cardiac myocytes

Cardiac muscle does not contain a copopulation of myogenic cells and is mitotically inactive; hence, any regenerative capacity of the myocardium most likely originates from viable fragments of damaged cells rather than mitogenic activity. To assess the extent of such tissue recovery, single doses of the drug bupivacaine were used to induce degeneration of rat ventricular myocytes, and histological evidence for tissue recovery was sought. Up to 1 wk posttreatment, extensive degeneration was found around the injection site. At 2 wk, evidence of regeneration could be seen, and at 3 wk posttreatment, some relatively normal looking tissue was found.