Articles : Low Intensity Exercise Suppresses Pathological Cardiac Hypertrophy Related Gene Expression in SHR

Journal of Exercise Nutrition & Biochemistry 2004;8(3):267-274.

Abstract

This study determined the effects of exercise training on cardiac function and myocardial gene expression, because we hypothesized that how exercise training prevents pathological hypertrophy in the left ventricle by modulation of myocardial genes. We used the spontaneously hypertensive rat (non-exercise SHR, n = 12) as a model of pathological hypertrophy and exercise-trained SHR rats (n = 12, treadmill exercise for 12 wk) as a model of physiological hypertrophy. We also used sedentary Wistar-Kyoto rats as the control group (n = 12). Exercise-trained SHR expressed clear adaptive changes such as reduced body weight, heart rate, blood pressures, and cardiac wall thickness. The mRNA expression of angiotensin converting enzyme (ACE), endothelin-1 (ET-1), brain natriuretic peptides (BNP) in the left ventricle was significantly higher in the non-exercise SHR than in the WKY and the exercise-trained SHR, whereas mRNA expression of caveolin-3 and eNOS in the left ventricle was significantly lower in the non-exercise SHR than in the WKY and the exercise-trained SHR. These findings suggest that exercise training prevents pathological hypertrophy in the left ventricle by modulation of myocardial genes. In conclusion, the exercise-trained SHR showed improved cardiac function, including reduced body weight, hemodynamic profiles, and cardiac wall thickness, as distinct from the pathological cardiac adaptation in the non-exercise SHR. Finally, exercise training prevents pathological cardiac hypertrophy in the left ventricle by altering myocardial genes.

Key Words: Spontaneously hypertensive rat, treadmill exercise, pathological cardiac hypertrophy, myocardial genes