The Effects Of Life Style On The Expression Of APN,APPL1and GLUTt4in Skeletal Musrje Of Insulin Resistance Rats

Background Adiponectin (adiponectin, APN) as an adipocytokine was first found inadipose tissue that have the effect of improving the insulin resistance,anti-inflammation and anti-atherosclerosis.In recent research,it found that the skeletalmuscle also express APN.Adaptor protein containing PH domain,PTB domain andleucine zipper motif1(APPL1) can bind with adiponectin receptor,participate inmetabolism related signal passway and increase insulin sensitivity,regulate glucolipidmetabolism.Glucose transporter protein4(GLUT4) is the main glucose transporter inskeletal muscle tissue and it can regulate glucose uptake and utilization.Diet restrictionand exercise is the common lifestyle used to lose weight and improve insulinresistance.This study establish model of insulin resistance by high-fat-diet obese ratsand investigate the effect of diet and exercise intervention on the expression ofAPN,APPL1and GLUT4in skeletal muscle that in order to approach the role ofadiponectin and APPL1in skeletal in the process of glucose metabolism.Objective To establish the rats model of skeletal insulin resistance(IR) andinvestigate APN,APPL1,GLUT4impacting on IR through diet restriction and exerciseinterventions and their correlation in skeletal muscle.Methods60male SD rats of4weeks age were randomly divided into two groups：normal control group (NC group) and high-fat diet group(HD group).The rats of NCgroup were given normal chow and HD group were given high-fat diet.After12 weeks,the fat rats modeled successfully were randomly divided into high fat group(HFgroup),diet restriction group(DR group),exercise control group(EC group)and dietrestriction combination with exercise control group(DE group).The rats of NC groupwere fed with normal chow and HF group with high-fat diet.The rats of EC groupassigned to swimming and given high-fat diet.DR group was given dietary restrictionsand each rat of which was administered to feed70%chow of HF group rat eatendaily.DE group was treaded with swimming exercise combination with dietaryrestrictions.After six weeks, the body weight of rats(BW) was measured underanesthesia,fasting blood glucose(FBG),fasting insulin(FINS),triglyceride(TG), totalcholesterol(TCH) was detected,and measured triglyceride(TG) content of skeletalmuscle tissue.To observe the expression and positioning of APN,APPL1and GLUT4in skeletal muscle tissue using immunohistochemical.To detect the expression and totalamount of APN,APPL1in skeletal muscle and the expression of GLUT4in cellmembrane using Western-blot method.Results1,Body weight(BW),triglyceride(TG),total cholesterol(TCH),fasting bloodglucose(FBG),fasting insulin(FINS) and HOMA-IR index of HF group weresignificantly higher than those of NC group(P<0.05),the TG level in skeletal muscletissue of HF group increased significantly comparing with NCgroup(P<0.05).Comparing with HF group,BW,TG,FBG,FINS,HOMA-IR and thecontent of TG in skeletal all down regulated than those in EC group(P<0.05),but notTCH(P<0.05).BW,TCH,FBG, FINS,HOMA-IR and the content of TG in skeletal alldown regulated in DR group(P<0.05),but notTG(P<0.05).BW,TG,FBG,FINS,HOMA-IR and the content of TG in skeletal all downregulated in DE group(P<0.05). There were no statistical differences betweenEC,DR,ED groups of BW,TCH,FBG,FINS, HOMA-IR and the content of TG inskeletal muscle.2, Immunohistochemical results: APN, APPL1and GLUT4can express in skeletal muscle tissue, APN mainly express in the cell membrane andmuscle bundle membrane, APPL1and GLTU4express in the cell membrane and cellcytoplasm. The OD value of APN,APPL1,GLUT4in HF group was down regulatedthan the NC group(P<0.05);compared with HF group,the OD value ofAPN,APPL1,GLUT4in DE,EC,DR group were increased(P<0.05); there was nodifference of APN,APPL1,GLUT4of OD value between DE,EC and DRgroup(P>0.05).3,Western-blot: the expression of APN，APPL1and GLUT4in skeletalmuscle of HF group were lower than NC group(P<0.05); the expression ofAPN,APPL1and GLUT4EC,DE group and the expression of APPL1and GLUT4inDR group was higher than HF group in rats skeletal muscle (P<0.05). There was nodifference of expression of APN between HF and DR group(P>0.05).There were nodifferences of expression of APN,APPL1,GLUT4in skeletal muscle between DE,ECand DR group(P>0.05).4,Correlation analysis: The expression of APN,APPL1andGLUT4in skeletal muscle were negatively correlated with FBG、HOMA-index and thecontent of TG in skeletal muscle (P<0.05), the expression of APN and APPL1werepositively correlated with GLUT4in skeletal muscle (P<0.05).Conclusion1, High-fat diets could lead to obesity and metabolic disorder of glucoseand lipid in rats，which cause insulin resistance. Dietary restriction and exercise couldreduce the weight of obese rats, regulate the metabolism disorder, improve thelipotoxicity and insulin resistance in skeletal muscle.2, APN,APPL1and GLUT4canexpress in skeletal muscle tissue.The expression of APN,APPL1and GLUT4inskeletal muscle reduce in insulin resistance rats and the the expression of APN,APPL1and GLUT4in skeletal muscle increase when the rats with insulin-resistance wereimproved through diet and exercise.3,The expression of APN,APPL1and GLUT4inskeletal muscle is significantly correlated with insulin resistance and the lipid contentin skeletal muscle.APN and APPL1in skeletal muscle may improve glucose metabolism and IR.