Exercise attenuates diet-induced arteriosclerosis in the adult rat.

The present investigation was conducted to assess the effects of exercise on diet-induced arteriosclerosis in retired breeder rats. Thirty-two 8- to 9-mo-old male Sprague-Dawley rats were allocated to one of four treatment groups: hypercholesterolemic diet-exercise (HE), hypercholesterolemic diet-sedentary (HS), normocholesterolemic diet-exercise (NE) and normocholesterolemic diet-sedentary (NS). The hypercholesterolemic diet contained 10% lard and 0.4% cholesterol. Exercise consisted of running on a motor-driven treadmill at an 8% grade 1 h per day at 0.5 mph, 6 d weekly for 5 mo. A histological assessment of the aortas demonstrated that although grossly visible atherosclerotic plaques were absent, there were significant microscopic differences among groups in the thoracic aorta, iliac bifurcation and aortic arch. Aortic histopathological changes were greatest in cross sections from rats in the HS group. The accumulation of collagen and sulfated mucosubstances was greater in the HS versus HE group. Our results demonstrate a beneficial effect of exercise on diet-induced histopathological changes in the aortas of male retired breeder rats.