Weight Gain and Oxidative Stress in Midlife Lead to Pathological Concentric Cardiac Hypertrophy in Sedentary Rats

Background: Midlife is associated with the development of various cardiovascular diseases such as coronary artery disease, hypertension, and heart failure. The present study aimed to investigate the effects of midlife on cardiac hypertrophy in sedentary rats and its relationship with body weight and oxidative stress. Methods: In this experimental study, 10 rats aged 11 - 14 months and 10 rats aged 4 months were used. After keeping the rats under normal housing condition for 10 days, they were slaughtered, and the dimensions of the heart, the extent of heart tissue fibrosis, and levels of H2O2 were measured. Student’s t-test and linear regression were used for the statistical analysis. Results: The findings of this study showed that midlife with low physical activity increases heart weight (P = 0.001), body weight (P = 0.001), and hydrogen peroxide (H2O2) levels (P = 0.001) resulting in a significantly increased ventricular wall thickness (P = 0.001) and ventricular diameter (P = 0.001). The increase in body weight and H2O2 by middle age was significantly associated with an increased ventricular wall thickness (P = 0.001), ventricular diameter (P = 0.001), and heart weight (P = 0.001). Also, there was a significant positive relationship between body weight gain and H2O2 level (P = 0.001). Conclusions: Midlife with low physical activity is associated with pathological concentric cardiac hypertrophy in rats, and subsequently, with weight gain, increased H2O2, increased heart weight and left ventricular wall thickness, and to some extent, left ventricular internal diameter.