Effect Of Exercise, EGCG And L-carnitine On Lipid Metabolism And Energy Homeostasis In Fat-fed Obese Rats

Objective:To investigate the weight-reducing effect of aerobic exercise plus EGCG, L-carnitine or EGCG-L-carnitine mixture, and to probe their improve effect on lipid and energy metabolism in obesity rats.Method:We induced high-fat-diet obesity animal model in4-weeks-old male Sprague-Dawley rats. Dividing the obese rats to5group randomly:obese control group (F), exercise group (S), S plus EGCG group (E), S plus LC group (L), S plus E-L mixture group (EL). There were6rats in each group, and all animals fed a fat-rich diet. Choosing medium-to-low-intensity treadmill exercise, and EGCG or L-carnitine was fed to rats by gavage at30mg/kg for6weeks. The level of serum lipid, lipoprotein lipase and hepatic lipase activities in liver, the expression of HSL protein in epididymal adipose tissue and UCP1in brown adipose tissue were measured.Result:1)The body weight decreased obviously in the experimental groups compared with obese rats (P<0.05). And the body weight in S plus E-L mixture group decreased more than exercise group (P<0.05).2) The level of serum TG was significantly reduced by each treatment (P<0.01), but serum TC showed a trend of decrease and HDL-C had an increase trend (P>0.05). S plus EGCG or L-carnitine or E-L mixture could induce a lower level of serum TG than exercise alone (P<0.01), but S plus E-L mixture could reduce lower serum TC and increase more HDL-C than exercise rats (respectively P<0.05, P<0.01).3) S plus EGCG or L-carnitine or E-L mixture improve the lipase activities in liver relative to obese control (respectively P<0.01, P<0.05, P<0.01), and exercise alone have no effect on the lipase activities in obese rats (P>0.05). Specifically, the lipase activities in S plus EGCG or E-L mixture group were higher than them in exercise group and S plus LC group (P<0.05).4) The content of HSL protein in epididymal adipose was elevated obviously by each treatment (P<0.01). No significant difference between the experimental groups (P>0.05) except that the S plus EGCG group enhance the HSL protein concentration than exercise (P<0.05).5) Neither aerobic exercise nor exercise with L-carnitine administration have an elevation effect on the UCPl protein expression in BAT in obese rats (P>0.05). Just S plus EGCG or E-L mixture could rise the concentration of UCP1protein in BAT (P<0.05).Conclusion:1) Both aerobic exorcise and exercise combine with EGCG or/and LC treating the obese rats could distinctly reduce the body weight, improve serum lipid through elevating the lipase activities in liver, and promote fat mobilization and oxidation through enhancing the HSL protein content in adipose tissue.2) But exercise alone or exercise plus LC have no effect on thermogenesis in BAT in obese rats, just EGCG enhance substrate utilization through increase the UCP1protein concentration.3) EGCG could cooperate with aerobic exercise to improve dyslipidemia and the lipase activities, HSL protein expression, while L-carnitine could cooperate with exercise to improve the serum lipid levels only.4) The effect of exercise plus E-L mixture administration on weight-reducing integrates the action of exercise, EGCG, and L-carnitine respectively.