Improvements of Atherosclerosis and Hepatic Oxidative Stress are Independent of Exercise Intensity in LDLr-/- Mice

Abstract

Cardiovascular diseases are the main causes of death in the Western world and are manifested by atherosclerosis. Depending on its intensity, regular aerobic exercise may be either beneficial or harmful to the atherosclerosis process. The aim of this study was to verify the effects of aerobic exercise training of different intensities on the profile of atherosclerotic lesions and serum lipid, and in the hepatic oxidative balance of low-density lipoprotein receptor-deficient (LDLr-/-) mice previously developed with atherosclerosis. All animals were submitted to a three-month high-fat and high-cholesterol diet regime. The animals were then randomly divided into no exercise (G1, n=9), low-intensity aerobic exercise (G2, n=10, 8 weeks of treadmill running, 30 min/day−1 at 8-10 m/min−1) and moderate-intensity aerobic exercise (G3, n=10, 8 weeks of treadmill running, 30 min/day−1 at 10-16m/min−1) groups. Serum total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C) and triglycerides (TG), and oxidative damage (protein carbonyls and lipid hydroperoxides) were measured. The activity of catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GPx) in the liver tissue was assessed. G2 (0.015±0.005cm2) and G3 (0.014±0.001cm2) presented lower aortic fat deposition than G1 (0.039±0.005cm2). G2 and G3 exhibited higher HDL-C, TG and CAT activity, but lower lipid peroxidation and carbonyl protein than G1. SOD values were higher in G3 than G2 and G1, and GPx was higher in G2 than in G3 and G1. Our protocols of low- and moderate-intensity aerobic exercise training (30 min daily for 8 weeks) induced similar benefits in LDLr-/- mice with atherosclerosis.