Effects of Diet with Different Saturated Fat Content on Lipid Metabolism and Risk Factors of Cardiovascular Diseases in Mice

Abstract

Background: A high-fat diet is an important risk factor for cardiovascular diseases (CVD). A diet high in saturated fat leads to the development of hypertension and CVD by increasing the serum concentration of angiotensin converting enzyme. However, different sources of saturated fats do not have the same cardiovascular risks. The effect of diets containing different fat concentrations on cardiac function is not clear. We explored the effects and mechanisms of diets containing different concentrations of saturated fat on lipid metabolism, cardiac function, and CVD risk factors. Methods: Healthy male C57BL/6 mice aged 12–14 weeks were fed with normal diet or diets containing different concentrations of saturated fat for 8 weeks as follows: normal diet group and 10%, 20%, and 30% saturated fat content groups. At the end of the intervention period, body weight was measured. Fasting for 12 h, left ventricular ejection function measured by M-mode echocardiography, and serum triglyceride and cholesterol levels were measured. The calcium transient was measured in isolated cardiomyocytes, and the amplitude of calcium transient change (F/F0) and calcium recovery rate in myocardial cells were measured. The mRNA and protein expression of fatty acid-binding protein 3 (FABP3) and fatty-acid binding protein 4 (FABP4) were assessed. Results: Weight gain of mice in each saturated fat group was higher than that in controls. The levels of fasting blood glucose, and serum total cholesterol and triglyceride in mice fed a 30% saturated fat diet were significantly higher than those in control mice. The ejection fraction of mice in each saturated fat group was lower than that in controls. The calcium recovery rate of cardiomyocytes in the 10%, 20%, and 30% saturated fat groups was significantly higher than that in controls. The mRNA expression of FABP3 and the mRNA and protein expression of FABP4 in the 20% and 30% saturated fat groups were significantly up-regulated. Conclusions: This study demonstrates that eating a diet containing 10%, 20%, and 30% saturated fat for 8 weeks increased body weight, blood sugar, and blood lipids; affected cardiac function; and adversely affected cardiomyocyte contraction. The decrease of heart function induced by saturated fat diet may be related to FABP4 up-regulation.