Effects Of Exercise On Lipid Metabolism In Rats Fed With High Fat Diet And Its Mechanism

Objective:To observe the effects of Sirtl on lipolysis promoted by exercise of high-fat diet rats and explore partial mechanism. Then provide theoretical basis for the role of exercise on lipid metabolism and obesity prevention.Methods:44Male Sprague-Dawley (SD) rats (aged6weeks) were randomly divided into four groups:normal diet control group (group C, n=10), normal diet+90min exercise group (group CE, n=12), high-fat diet group (group H, n=10), high-fat diet+90min exercise group (group HE, n=12). Exercise program:Took90min non loaded-swimming, time in day1of the first week lasted15min and thereafter ascended15min a day until reached90min. From the second week, rats in swimming group underwent long-term (90min6days/week for8weeks) non loaded-swimming exercise. Food consumption of each group was measured daily and rats were weighed every Sunday. At the end of the experiment, levels of TC, TG, HDL-C, LDL-C and FFA in serum, the expression of Sirtl mRNA and protein, PPARy mRNA, Perilipin mRNA, HSL mRNA in adipose tissue were estimated.Results:1. There was no significant difference in initial weight of the rats. After the treatment, the weight of rats was significantly lower in group CE than in group C (P<0.05), group H was significantly higher than group C (P<0.05) and group HE was significantly declined than group H (P<0.01);2. Compared with group C, body fat and lipid ratio in group H increased remarkably (P<0.01); body fat and lipid ratio in group HE decreased markedly (P<0.01) compared with group H; compared with group HE, body fat in group CE declined notablely (P<0.05) and lipid ratio decreased remarkably (P<0.01);3. Blood biochemical parameters:Compared with group C, levels of TG, TC and LDL-C in serum raised significantly in group H (P<0.01), level of FFA increased remarkably (P<0.05) while HDL-C decreased markedly (P<0.05). Compared with group H, there was a significant decline in the levels of TG, LDL-C of serum in group HE (P<0.01), and a downward trend in TC. Besides, FFA in serum decreased notablely (P<0.05);4. Compared with group C, Sirtl in rats adipose tissue of group H decreased significantly (P<0.05), while Sirtl in group HE raised compared with group H, but there was no significant difference (P=0.371>0.05);5. Compared with group C, Sirtl (P<0.05) and HSL (P<0.01) significantly decreased in group H. Besides, PPARy (P<0.01) and Perilipin (P<0.05) raised remarkably. In comparation with group H, Sirtl and HSL increased significantly (P<0.05) in group HE, while PPARy and Perilipin declined markedly (P<0.01).Conclusion:1. There was a significant decrease in TG, TC, body weight and lipid ratio of rats after swimming, indicated that90min swimming exercise could effectively promote lipolysis and prevent obesity caused by fat deposition.2. eight weeks of swimming exercise can increase Sirtl expression in adipose tissue of rats, the activity of PPAR gamma is restrained; PPAR gamma further cut the expression of perilipin,and reduces Perilipin protein synthesis, on the other hand weakened in the barrier protection of fat, adding the transposition and activity of HSL, so as to promote adipose decompose, inhibit fat deposition.