Echocardiographic evaluation of cardiac structure and function during exercise training in the developing Sprague-Dawley rat.

Echocardiography is a widely used evaluation tool in cardiovascular research. Although rats are a common model in such research, normal echocardiographic values for young, developing rats have not been established. Furthermore, whether exercise during the developmental phase of the lifespan affects the structure or function of the heart is unclear. Male Sprague-Dawley rat pups (21 d) were assigned randomly to a nonexercise or voluntary exercise group for 12 wk. Echocardiograms were obtained before and at weekly intervals during the 12-wk observation period. Maturation resulted in changes in many echocardiographically derived variables, whereas voluntary exercise failed to alter the development of cardiac structure or function. This study provides normal echocardiographic variables for developing male rats and provides evidence that exercise during the developmental phase of the lifespan has little effect on cardiac morphology and function as assessed by echocardiography. Copyright 2011 by the American Association for Laboratory Animal Science