Journal of Applied Physiology, Vol 66, Issue 4 1649-1655, Copyright © 1989 by American Physiological Society
Prevention of myocardial disease in JCR:LA-corpulent rats by running
J. C. Russell, R. M. Amy, V. Manickavel, P. J. Dolphin, W. F. Epling, D. Pierce and D. P. Boer
Department of Surgery, University of Alberta, Edmonton, Canada.
The JCR:LA-corpulent rat is a congenic strain that, if homozygous for the
cp gene, is obese with a very low-density lipoprotein hyperlipidemia and is
insulin resistant. The male corpulent rats develop atherosclerotic lesions
of the major arteries and myocardial lesions. Corpulent and lean male rats
were induced through mild food restriction to run intensively
(approximately 6,000 m/day) from 6 wk to 6 mo of age. Food restriction,
especially when coupled with running, lowered all classes of lipids in the
whole serum of corpulent rats. The principal changes in lipid
concentrations were in the very low-density lipoprotein fraction. Food
restriction caused a significant drop in fasting insulin levels of
corpulent rats and decreased beta-cell hyperplasia. Both effects were more
marked in the running animals. There was a significant decrease in
myocardial lesion frequency in the food-restricted corpulent rats and an
absence of lesions in the running rats. The results indicate that intensive
physical activity can largely correct the lipid abnormalities and insulin
resistance of this atherosclerosis-prone strain, and these changes are
associated with inhibition of the disease process. However, moderate food
restriction has similar effects, and the greater effects seen with
intensive running may simply reflect an effectively more severe metabolic
restriction in the presence of the exercise.
