Effects Of Metformin And Aerobic Exercise On Serum Visfatin And Visfatin Protein Expression Levels In Different Tissues Of High-fat-diet-fed Obesity Rats

Background The central link of metabolism syndrome is insulin resistence,the main reason of which is central obesity. Visfatin is a kind of secretory protein generated by adipose tissue,Which is mainly secreted by adipose tissue of internal organs, and also expressed in liver, pancreas, heart, placenta, lung, kidney etc. Researches show that Visfatin can play an insulin-like effect which is important to improve insulin sensitivity. As is known to all, both metformin and aerobic exercise can reduce weight and improve insulin sensitivity,but the relation between Visfatin and those two factors has been rarely reported.In this study,we try to observe the effects of aerobic exercise and metformin on Visfatin in obesity rats fed with high fat diet and to preliminarily investigate the mechanism.Objective To observe the effects of metformin and aerobic exercise on Visfatin of serum,epididymis adipose tissue ,subcutaneous adipose tissue and liver in obesity rats fed with high fat diet.Methods 70 male Sprague-Dawley(SD) rats were randomly divided into the normal diet group (ND) with 10 rats, fed with normal chow , the high fat diet group (HD) with the remaining 60, fed with high fat diet.After 16 weeks, the average BW of HD group were over 20% higher than ND group. All the rats were weighed under anesthesia. The triglyeride(TG), total cholesterol(TCH), fasting blood glucose(FBG), fasting insulin(FINS) and Visfatin in the serum were measured. Obesity model (n=40) was randomly divided into four groups accepting intervention for 6 weeks: group F,group M, group T and group MT,with 10 rats in each groups. Group M was treated with metformin (200mg/kg.d), group T was assigned to swimming exercise, and group MT was treated with the combination of metformin(200mg/kg.d) and swimming exercise. Group T, group F and group ND were treated with distilled water . The body weight (BW), triglyeride(TG), total cholesterol(TCH), fasting blood glucose(FBG), fasting insulin(FINS) and Visfatin in the serum were measured again at the end of 22nd week.After all the rats were killed, the protein levels of Visfatin in different tissues(epididymis adipose tissue ,subcutaneous adipose tissue and liver) were analyzed with Western blot.Results①After 16 weeks of high-fat diet, BW, FBG, FINS ,TG and TCH 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).②Visfatin in the serum in obesity model were higher than that in ND group(P < 0.01).③After 6 weeks'treatment BW, FBG, FINS ,TG and TCH levels in the group M, T and MT decreased compared to group F (P <0.01 or P <0.05).④Visfatin in the serum in the group M, T and MT decreased compared to group F(P <0.01 or P <0.05).⑤There is no statistical difference of BW, FBG, FINS ,TG, TCH and Visfatin levels in the group M, T and MT.⑥Visfatin protein expression levels of group F in EAT, SAT and LT increased compared to group ND(P <0.05).⑦Visfatin protein expression levels of group M, T and MT decreased in compared to group F in EAT, SAT and LT(P <0.05).⑧BW,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 ).Conclusion Metformin,aerobic exercise , the combination of metformin and aerobic exercise can improve the metabolism syndrome of rats fed with high fat diet to certain extent, and decrease the concentration of Visfatin of serum, epididymis fat, subcutaneous fat and liver in obesity rats.