Muscle Regeneration

Abstract

Ethylenedinitramine (EDNA), a plant growth stimulator (1) and high impact explosive, ameliorates the symptoms of dietary and hereditary muscular dystrophy in laboratory animals (2). These beneficial effects have been correlated with enhanced muscle regeneration. In mechanically injured muscle, EDNA increases the regenerative yield most dramatically when its administration is timed to coincide with a certain critical period (3) before the new fibers appear. We speculated that su banes t he tic concentrations of ethylene, too, might increase muscle regeneration.

Materials and Methods. Male mice, Re 129 dydy, 3 months of age, were paired in two groups, littermates being represented in each group. One group was exposed to ambient air and the other to USP grade ethylene. The cage containing the latter was enclosed in a gas-proof Saran bag. Ethylene-air mixtures were delivered at 1.8 liters/min. Animals inhaled ethylene continuously for 7 days, three at a concentration of 5.7% and the remaining four at 0.2%. Ethylene concentrations were determined at the Ethylene Analysis facilities of The Dow Chemical Company. Upon termination of exposure, animals were sacrificed and tibialis anterior muscle was dissected out, fixed in formalin, and paraffin sectioned serially and tangential to the anterior surface of the muscle belly. Sections were mounted in even rows convenient for random sampling. Slides were stained with Ehrlich's hematoxylin and eosin.