The Effect Of Rosiglitazone On Expression Of Lipid Droplets Related Proteins In Skeletal Muscle Of Obese Rat

Objective To examine the effect of obesity on lipid and expression of lipid droplets related proteins in skeletal muscle. Discuss the effect of rosiglitazone intervention on expressions of lipid droplets related proteins in skeletal muscle.Methods 32 male Wistar rats, 6-week-old, were assigned to two groups, obese group(n=24) rats were fed with high fat food; control group (n=8) rats were fed with chow food. At the end of the 12th week, half of obese group rats were randomly chose to be fed with rosiglitazone (3mg·kg﹣1·d﹣1, Rosi group) for 2 weeks, and the other animals were fed with saline as control. After 14 weeks follow-up, weight, body length, plasma biochemical parameters were measured and then hyperinsulinemic-euglycemic clamp to assess insulin sensitivity of rats was proceeded. After that, the rats were sacrificed for detecting the levels of skeletal muscle lipid and expressions of lipid related proteins. Skeletal muscle triglyceride(TG), diacylglycerol(DAG) were investigated by biochemical methods. The expressions of phosphorylated perilipin and caveolin-3 were measured by western blotting.Results (1) In comparison with control group, weight, body length, Lee index, epididymal and retroperitoneal fat pad were increased significantly in obese group, respectively. (2) In obese rats, plasma TG, free fatty acid(FFA) and fasting insulin (FINS) level were increased more than control group, glucose infusion rate(GIR) was 23% of control group, but there was no difference in total cholesterol(TC) and fasting blood glucose(FBG) between obese and control groups. (3) The expressions of phosphorylated perilipin and caveolin-3 in obese group were significantly increased more than that in control group. (4) In comparison with obese group, abdomen fat, plasma TG, FFA, FINS, skeletal muscle TG and DAG in Rosi group were decreased significantly, GIR in Rosi group was comparable with that in control group. And the expressions of phosphorylated perilipin and caveolin-3 were further increased.Conclusion In obese states, lipid content in skeletal muscle was increased and expressions of lipid droplets related proteins phosphorylated perilipin and caveolin-3 were also increased. Rosiglitazone could upregulate the expressions of phosphorylated perilipin and caveolin-3 in skeletal muscle, which may be a defence mechanism to protect skeletal muscle when there was lipid overspill.