GLP-1 Analogues Reduce The Weight Of DIO Rats By Inhibiting The Activation Of Hypothalamic Microglia

Part 1.Induction and establishment of a rat model of obesity induced by high-fat diet(DIO)Objective: Using lard high-fat diet and purified high-fat diet to intervene weaning SD rats for 12 weeks to verify successful modeling of obese rats Screening the obesity model that mimics the environmental and pathophysiological characteristics of simple obesity in humans.Methods: SD rats were randomly divided into normal,sham and shunt groups.SD weanling rats were randomly divided into three groups: D1 group,where rats were fed by lard oil HF diet;D2 group,where rats were fed by purified HF diet;C group,where rats were fed on chow.After 12 weeks,Diet-induced obesity rats(top 33% based on the weight)were selected for further study,and the rest rats from group D1 and D2 were excluded.The food intake and the body weight were weighted daily and weekly,respectively.The subcutaneous,visceral and total fat contents of rats were measured by 256-row CT scan and the Lee index were calculated accordingly.Serum leptin and insulin levels were quantified.The pathology in liver and adipose tissues were analyzed by HE staining.Oral glucose tolerance test(OGTT)was used to compare the glucose tolerance ability.Serum total cholesterol(T-CHO),high density lipoprotein(HDL-C),low density lipoprotein(LDL-C),triglyceride(TG)and inflammatory cytokines IL-6,TNF-alpha were detected as well.Results: After 12 weeks,the body weight,subcutaneous fat,visceral fat,total body fat mass,area under blood glucose curve and the levels of serum insulin,leptin,T-CHO,LDL-C,TG,IL-6 and TNF-? in group D2 were significantly increased compared to those of group C and group D1.HDL-C of group D2 was markedly lower than that in group C(P<0.05).The visceral fat,total fat content and HDL-C in group D1 were significantly different from those of group C(P<0.05).Steatosis and enlarged adipocyte were found in the livers of rats in group D1 and D2,and the lesions was more significant in group D2.Conclusions: The use of purified high-fat diets for the induction of obesity associated with metabolic abnormalities,visceral steatosis,and peripheral chronic inflammation is more effective.Only visceral steatosis-related models can be induced to use the more economical lard high-fat diet.In this study,purified high-fat diet-induced obese rat model was used to simulate human simple obesity.Part 2.Liraglutide lower body weight in the Diet-induced Obesity Rat by acting on hypothalamic microgliaObjective: By analyzing the activation and influence of liraglutide on hypothalamic microglial cells in DIO rats,the hypothalamic central inflammation is improved and body weight can be effectively reduced.Methods: The DIO rat model established in the first part was divided into continuous high-fat diet group(DH),liraglutide group(DL)and DL paired diet group(DP).The first part of the control group rats continued to be the control group(C).In the DL group,liraglutide 200ug/kg was injected subcutaneously,and the control group was injected with the equal volume 0.9% Nacl liquid,all rats were injected twice a day for 6 weeks.The changes of body weight in each group were measured the expression of IL-1?,IL-6,TNF-? and SOCS3 m RNA in hypothalamus was detected by q RT-PCR.The expression of NPY,Ag RP,POMC,and CART protein was detected by Western blot.Immunofluorescence antibody technology detects expression of pro-apoptotic protein(BAX),anti-apoptotic protein(BCL2)and microglia activation status marker protein IBA-1.Results: After 6 weeks of intervention,the body weight of group DL was significantly lower than that of group DH and DP(P<0.05),and q RT-PCR was compared with IL-1?,IL-6,TNF-? and SOCS3 m RNA.The expression of inflammatory factors in group DL was significantly lower than that in group DH and DP(P<0.05).The expression of NPY,Ag RP,POMC and CART protein was detected by Western blot.The inhibition of appetite protein by POMC and CART in group DL was significantly higher than that in DH and DP groups(P<0.05).There was no significant difference in the expression of NPY and CART.The expression of apoptosis related protein BAX,BCL2 and microglia activation marker protein IBA-1 protein detected by Immunofluorescence were compared.The BAX expression in group DL was significantly lower than that of DF and DP group(P<0.05).The BCL2 expression of DL group was higher than that of DF and DP group(P<0.05).The density of microglia in group DL was significantly lower than that in DF and DP group(P<0.05).There was no significant difference between the three kinds of proteins between DP and DF(P>0.05).Conclusions: The GLP-1 analogues,which can inhibit the activation and proliferation of microglia,improve the inflammatory state of the feeding regulation center,inhibit the apoptosis of the feeding related neurons,and inhibit the increase of the expression of appetite POMC/CART protein,and play an effective weight reduction effect.