ABSTRACT
Objective To study the effect of aerobic exercise and dietary intervention on lipid metabolism in metabolic syndrome rats, and investigate the possible mechanism mediated by peroxisome proliferator-activated receptorα(PPARα). Methods After one-week feed-ing, Sprague-Dawley rats were randomly divided into blank control group (CC group) and model group which were feed in high-fat-and-salt diet for 18 weeks to establish a metabolic syndrome model. Then, the metabolic syndrome rats were randomly divided into model control group (MC), the model high-fat diet group (MHE) and the model general died exercise group (ME). ME and MHE groups were forced to run on a treadmill for twelve weeks at the same time. The weight of perirenal fat, blood free fat acid (FFA), and blood lipid were determined. The expression of PPARαmRNA in myocardium was detected by RT-PCR. Western blotting was applied to detect the protein expression of PPARαin myocardium. Results Compared with CC group, MC group showed significant increase in body weight, perirenal fat weigh, FFA, and blood lipid (P<0.05), and significant decrease in PPARαmRNA and protein expression (P<0.01) in myocardium. Compared with MC group, ME and MHE groups showed significant decrease in body weight, perirenal fat weight, triglyceride (TG), and showed significant in-crease in high-density lipoprotein (HDL), and the expression of PPARαmRNA and protein in myocardium (P<0.05). Compared with MHE group, ME group showed decrease in low-density lipoprotein (LDL) (P<0.05), and increase in the expression of PPARαmRNA and protein (P<0.01). Conclusion Aerobic exercise may activate the expression of PPARα, enhance the utilization of fatty acid, reduce body mass and visceral fat mass, improve the dyslipidemia and then regulate lipid metabolism in metabolic syndrome rats.
ABSTRACT
Objective To explore the influences of proliferation and differentiation of preadipocytes on high fat diet-induced obesity and obesity prevention through exercises in rats.Methods Forty male Sprague-Dawley rats were divided into a normal diet control group (C,n=8),a normal diet with exercises group (E,n=8),a high fat diet control group (H,n=14) and a high fat diet with exercises group (HE,n=10).Group C and group H kept sedentary,while group E and group HE underwent treadmill exercises at about 75％VO2max level.After 12 weeks of intervention,the body weight,epididymal,perirenal and retroperitoneal fat mass were recorded,and the total fat mass was determinated.Stereology method was used to calculate the number and average diameter of fat cells.Western Blotting was conducted to measure the expression of PPARγ and C/EBPα protein in adipose tissues.Results (1) The body weight and total fat mass of group H were significantly higher than those of group C (P＜0.01).Perirenal,retroperitoneal fat and total fat mass of group E and HE were significantly lower than those of group C and H respectively (P＜0.01).(2) The total fat cell number of group H was significantly higher than that of group C.The average diameter of fat cells in perirenal and retroperitoneal fat pads of group E were significantly lower than that of group C (P＜0.05,P＜0.01),while that of group HE in epididymal,perirenal and retroperitoneal fat pads was significantly lower than that of group H (P＜0.01).(3) Compared with group C,the expression of PPARγ protein of group E and H increased significantly in epididymal,perirenal and retroperitoneal fat pads (P＜0.01).The expression of C/EBPα protein of group H was significantly higher than that of group C in epididymal and perirenal fat pads (P＜0.01),the expression of C/EBPα protein of group E was significantly higher than that of group C in perirenal and retroperitoneal fat pads (P＜0.01),while the expression of C/EBPα protein of group HE was significantly lower than that of group H in perirenal fat pads(P＜0.01).Conclusion The proliferation and differentiation of preadipocyte was enhanced in the development of high fat diet induced obesity and exercises to prevent obesity,but its role and mechanisms were different.The high fat diet increases the number of fat cells which is a compensatory mechanism for the body to adapt to fat accumulation,while exercises might promote cell renewal and decrease the average size of fat cells which is an adaptive mechanism to improve fat storage.