Electro-acupuncture Promoting Lipid Metabolism Via Adenosine Receptors

Objective:To investigate the effects of electro-acupuncture(EA)on expression of adenosine receptor in the white adipose tissue(WAT)of diet-induced obese(DIO)mice,so as to reveal a novel mechanism of weight loss induced by EA.Methods:Sixty-three three-week-old C57BL/6 male mice were divided into chow diet group(n=21)and high fat diet group(n=42)randomly,and fed by normal diet and high fat diet for 12 weeks,respectively.In the high fat diet group,mice with body weight over 20%heavier than that of the chow diet group were considered as obese mice.All mice were divided into normal group(CD,n=8)and normal plus EA group(CD+EA,n=13),or obese group(HFD,n=9)and obese plus EA group(HFD+EA,n=14).The CD+EA group and the HFD+EA group were treated with EA at "Zusanli"(ST36)and "Neiting"(ST44)(2/15Hz,0.6-1.0mA)for 20 min,6 times a week for 4 weeks.Body weight,the change of body weight,ratio of WAT/body weight were evaluated.Thermogenesis,food intake,locomotor activity(XT+YT),total distance were analyzed by TSE phenomaster system,hematoxylin-eosin staining was used to observed the size of epididymal adipocyte,qPCR and Western Blot were applied to detect mRNA and protein levels of adenosine receptors and relative biomarkers in the adipose tissue,respectively.Results:1.Compared with the chow diet group,high fat diet significantly increased body weight in C57BL/6 mice after feeding for 12 weeks(P<0.01);23 out of 42 high fat diet mice were classified as obesity.After treatment,the body weight and the ratio of Epi-WAT/body weight of the CD+EA group were decreased than those in the CD group(P<0.05),the body weight and the ratio of Epi-WAT/body weight of the HFD group were increased than those in the CD group(P<0.05),the change of body weight in the HFD group was more than that in the CD group(P<0.01).Compared with the HFD group,the body weight and the ratio of Epi-WAT/body weight of the HFD+EA group were decreased after EA(P<0.05),the change of body weight was increased(P<0.01).TSE system analyse showed that the ratio of oxygen consumption(VO2)was reduced in the HFD group(P<0.05),the respiratory exchange rate(RER)and food intake were rised in the HFD group(P<0.05),compared to the CD group.In comparison with the HFD group,the thermogenesis(H1?H2),the rate of carbon dioxide produced(VCO2)and VO2 were increased in the HFD+EA group(P<0.05),the food intake was decreased in the HFD+EA group(P<0.05),while RER was no discrepancy(P>0.05).The locomotor activity(XT+YT)and total distance were no significant difference among the four groups(P>0.05),even in the night.HE staining showed us that the area of epididymal adipocyte of obese mice was larger than the normal mice(P<0.01),besides the areas in the CD+EA group and the HFD+EA group were decreased by EA(P<0.05,P<0.01).2.There was no obvious change in the expression level of A1R mRNA among the four groups(P>0.05).The expression of A2AR protein was decreased in the HFD group than that in the CD group(P<0.05),the expression of A2BR protein was no obvious difference between CD group and HFD group(P>0.05),and the fold change of A3R mRNA in the HFD group was lower than that in the CD group(P<0.01),the expression levels of A2AR and A2BR protein were increased by EA in the CD+EA group(P<0.05,P<0.01).In comparison with the HFD group,the expression levels of A2AR and A2BR mRNAs and proteins were significantly up-regulated in the HFD+EA group,respectively(P<0.05,P<0.01).The fold change of Tbx1 and Tmem26 mRNA in the HFD group were lower than those in the CD group(P<0.05),the expression level of PRDM16 of the BAT were decreased in the HFD group than the CD group(P<0.05).In comparison with the HFD group,the expression of Tbx1 and Tmem26 mRNA were up-regulated in the HFD+EA group(P<0.05),the expression levels of PRDM16,PGC-1?,and UCP1 of the Epi-WAT were increased,respectively(P<0.05,P<0.05,P<0.01),so as the PRDM16,UCP1 of the BAT(P<0.01).Compared with the CD group,the expression levels of pTH and pHSL protein were decreased in the HFD group(P<0.01,P<0.05),and they were increased by EA(P<0.01).Conclusion:EA intervention is able to reduce the body weight of DIO mice,which may be associated with its effects in regulating the expression of A2AR and A2BR in white adipose tissue,suggesting a novel mechanism of EA in accelerating peripheral lipid metabolism and energy expenditure,which may be innervated by the autonomic nervous system.