| BackgroundVisfatin known previously as pre-B cell colony-enhancing factor is the most recently identified peptide expressed in human visceral and subcutaneous adiopose tissue with a molecular weight of 52KD. Its amino acid sequence is highly conserved in each species and Visfatin is also widely expressed in muscle, liver, marrow and macrophage. Visfatin mimics the action of insulin through a distinct binding site on the insulin receptor, affects lipid profiles and promote the synthesis, differentiation and accumulation of adiopose tissue. Visfatin also plays roles in inflammation and the pathophysiology of atherosclerosis, regulates the maturity of vascular smooth muscle, and is a new bond linking glucolipid metabolism disorders and cardioascular diseases. Insulin-sensitizing agent Metformin is a widely used drug for diabetes in clinical work, which can target on adiopose tissue and have an impact on its endocrine metabolism. Swimming exercise,a kind of aerobic exercise, has a profound effect on nutrient balance and improves insulin sensitivity. As a result, exercise is widely advocated as a first-line treatment in the control of obesity, insulin resistance, and type 2 diabetes.Objectiveto observe the impact of treatment with metformin and swimming exercise and the adjunctive therapy on body weight, metabolic parameters, serum Visfatin and Visfatin protein expression levels in subcutaneus adipose tissue(SAT), perirenal adipose tissue (PAT) and muscle tissue (MT) of high-diet-fed obesity rats were determined,and the relationship between them were analysed.Method 70 SD rats were randomly divided into normal diet group (ND) with 10 rats and high fat diet group (HD) with the remaining 60.The ND group were fed with normal chow, and the HD group were fed with high-fat diet. Obesity model (n=40) was established from HD group after 16weeks and was randomly divided into four groups: Obesity group (OB), Metformin group (MET),swimming exercise group (SWI), and the combination of metformin and swimming exercise group (MAS) with 10 rats in each groups. MET group was treated with metformin (200mg/kg.d), SWI group was assigned to swimming exercise, and MAS group was treated with the combination of metformin(200mg/kg.d) and swimming exercise. SWI group, OB group and ND group were treated with distilled water . Body weight (BW), fasting blood glucose(FBG ), triglyceride (TG), total cholesterol (TCH), fasting insulin (FINS) and fasting Visfatin were detected before and after the 6 weeks of treatment. Visfatin protein expression levels in SAT, PAT and MT were determined by Western Blot.Resultsâ‘ BW, FBG, TG, TCH, FINS and Visfatin levels of each group in obesity model were higher than that in ND group with a statistical significance (P <0.01 or P<0.05). After 6 weeks'treatment BW, FBG, TG, TCH, FINS and Visfatin levels in the group of MET, SWI and MAS decreased compared to OB group (P <0.01 or P<0.05).â‘¡Visfatin protein expression levels of obesity group in SAT, PAT and MT, especially that of PAT increased compared to ND group(P <0.01 or P<0.05),and there was no statistical differences in Visfatin protein expression levels between SAT and MT. In SAT and PAT, Visfatin expression levels of the group of MAS, MET, and SWI especially MAS group decreased after intervention. Visfatin expression levels of the group of MAS, MET, and SWI in MT decreased with no statistical difference .â‘¢BW,TG,TCH,FBG,FINS were positively related to serum Visfatin levels(r=0.86, P<0.01; r=0.83, P<0.01; r=0.88, P<0.05; r=0.91, P<0.05; r=0.85, P<0.05 ),and serum Visfatin levels were positively related to Visfatin protein expression levels in perirenal adipose tissue (PAT) (r=0.95, P<0.05 ).ConclusionVisfatin which preferentially expresses in viscera adipose tissue may play a role in the glucolipid metabolism of obesity rats. Metformin and swimming exercise can down-regulate serum Visfatin and Visfatin protein expression levels in SAT and PAT but has no influence on that of MT. |
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