Effects Of Metformin And Aerobic Exercise On Serum Chemerin And Chemerin Protein Expression Levels In Different Tissues Of Obesity Rats

Background chemerin is a natural ligand for an orphan G protein—coupled receptors(GPCRs)一chemerin receptors,which is widespread in tissues. It is involved in regulating innate and adaptive immunity,bone development,and maintenance of norrnal function of skin.More recently,it has been reported that chemerin is an adipokine and its expression leve1 is associated with obesity.It has many biological effects including regulating adipogenesis and adipocyte metabolism,stimulating insu1in—dependent glucose uptake in adipocytes.As is known to all,both metformin and aerobic exercise can reduce weight and improve insulin sensitivity,but the relation between chemerin and those two factors has been rarely reported. In this study,we try to observe the effects of aerobic exercise and metformin on chemerin in obesity rats fed with high fat diet .Objective To observe the effects of metformin and aerobic exercise on chemerin of serum,epididymis adipose tissue, perirenal adipose tissue and liver tissue in obesity rats fed with high fat diet.Method 70 SD rats were randomly divided into normal diet group(NC) with 10 rats and high fat diet group(HF) with the remaining 60.The ND group were fed with normal chow,and the HF group were fed with high-fat diet.Obesity model(n=40) was established from HF 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 NC group were treated with distilled water.Body weight(BW),fasting blood glucose(FBG),triglyceride(TG),total cholesterol(TCH),fasting insulin(FINS)and fasting chemerin were detected before and after the 6 weeks of treatment. chemerin protein expression levels in SAT,PAT and MT were determined by Western Blot.Results①BW,FBG,TG,TCH,FINS and chemerin levels of each group in obesity model were higher than that in NC group with a statistical significance(P<0.01 or P<0.05).②After 6 weeks'treatment BW,FBG,TG,TCH,FINS and chemerin levels in the group of MET,SWI and MAS decreased compared to OB group(P<0.01 or P<0.05).③chemerin protein expression levels of each group in obesity model in SAT,PAT and LT increased compared to NC group(P<0.01 or P<0.05),chemerin expression levels of the group of MAS,MET,and SWI especially MAS group decreased after intervention.④BW,TG,TCH,FBG,FINS were positively related to serum chemerin levels,and serum chemerin levels were positively related to chemerin protein expression levels in perirenal adipose tissue(PAT).Conclusion Metformin,aerobic exercise,the combination of metformin and aerobic exercise can improve the Glucose and lipid metabolism disorder,insulin resistance of rats fed with high fat diet,and can down-regulate serum chemerin and chemerin protein expression levels in SAT,PAT and LT.