FA IMPROVES CARDIAC FUNCTION IN OBESE MICE BY ALLEVIATING OXIDATIVE STRESS AND REDUCING MYOCARDIAL FIBROSIS

Objective: To analyse the effect of folic acid (FA) on cardiac function in obese mice and to explore the possible mechanism(s). Methods: Sixty healthy male C57BL/6J mice, aged four to five weeks old, were randomly divided into three groups: group A (n=20) was given a normal diet, group B was treated with a high-fat diet and group C was treated with a high-fat diet + FA (FA dissolved in drinking water at a concentration of 20mg/L). Fasting blood glucose levels, body weight, heart weight and myocardial oxidative stress were measured after 14 weeks of feeding, and cardiac function (left cardiac ejection fraction, left ventricular short-axis shortening rate) was detected by echocardiography. Results: The fasting blood glucose levels and heart weight in group B were significantly higher than those in group A and group C (P<0.01 or 0.05), and the bodyweight in group B was obviously higher than that in group A (P<0.05). There was no significant difference in body weight between group B and group C (P>0.05). The results of the echocardiography show that the cardiac function of mice in group B was reduced markedly and the short axis shortening rate and left ventricular ejection fraction were significantly lower than those in group A (P<0.01). The short axis shortening rate and left ventricular ejection fraction in group C were better than those in group B, and the difference was statistically significant (P<0.05). The results of the Masson stain showed that the amount of collagen precipitation in the myocardial tissue and the degree of myocardial fibrosis in group B were remarkably higher than those in group A, while the amount of collagen precipitation in the myocardial tissue and the degree of myocardial fibrosis in group C were significantly improved from those in group B. The levels of antioxidant enzyme SOD, CAT and GSH in the heart tissue of mice in group B decreased, and the levels of CAT and GSH were significantly lower than those in group A and group C (P<0.05 or 0.01). However, there was no significant difference in SOD in the heart tissue of mice in each group (P>0.05). Conclusion: Supplementation of FA can significantly reduce fasting blood glucose levels, lighten heart weight and improve cardiac function in obese mice. The mechanism may be related to the relief of myocardial fibrosis and myocardial oxidative stress by FA.