基于下丘脑瘦素受体介导的JAK2/STAT3通路探讨穴位埋线治疗食源性肥胖大鼠的中枢机制

Exploring the Central Mechanism of Acupoint Catgut Embedding Therapy in Treating Rats with Diet-Induced Obesity Based on Hypothalamic LepR-Mediated JAK2/STAT3 Pathway

【目的】观察穴位埋线对食源性肥胖(DIO)大鼠体质量、脂代谢、血清瘦素和下丘脑瘦素受体(LepR)介导的Janus激酶2(JAK2)/信号转导和转录激活因子3(STAT3)通路mRNA及蛋白表达的影响。【方法】将40只雄性SD大鼠随机分成正常组10只和造模组30只。采用高脂饮食诱导建立DIO大鼠模型。造模成功后将成模大鼠随机分为模型组、埋线组和埋线+AG490(JAK2/STAT3通路阻断剂)组,每组10只。埋线组、埋线+AG490组于造模成功后第1、8、15、22天进行埋线,穴位选取中脘、水道、天枢、脾俞、胃俞、三焦俞,共治疗4次,埋线+AG490组穴位埋线治疗期间每天腹腔注射AG4901 mg/kg;正常组和模型组仅抓取固定。治疗前后测量体质量。治疗后检测脂代谢指标甘油三酯(TG)、总胆固醇(TC)、低密度脂蛋白胆固醇(LDL-C)、高密度脂蛋白胆固醇(HDL-C)以及血清瘦素水平,实时定量聚合酶链反应(RT-PCR)法检测下丘脑LepR、JAK2、STAT3的mRNA表达,Western Blot法检测下丘脑LepR、JAK2、STAT3的蛋白表达。【结果】治疗前,与正常组比较,模型组、埋线组、埋线+AG490组体质量均升高(P<0.01),与模型组比较,埋线组、埋线+AG490组体质量无显著性差异(P>0.05)。治疗后,与正常组比较,模型组体质量,瘦素及TG、TC、LDL-C水平升高,LepR、JAK2、STAT3 mRNA及蛋白表达水平降低(均P<0.01);与模型组比较,埋线组体质量,瘦素及TG、TC、LDL-C水平降低,LepR、JAK2、STAT3 mRNA及蛋白水平升高(均P<0.01);与埋线+AG490组比较,埋线组体质量,瘦素及TG、TC、LDL-C水平降低,LepR、JAK2、STAT3 mRNA及蛋白水平升高(P<0.05或P<0.01)。【结论】穴位埋线对DIO大鼠具有良好的减重降脂作用,其中枢机制可能与下调血清瘦素水平,激活下丘脑LepR介导的JAK2/STAT3通路有关。

Objective To observe the effects of acupoint catgut embedding therapy on body mass,lipid metabolism,serum leptin and mRNA and protein expressions of hypothalamic leptin receptor(LepR)-mediated Janus kinase 2(JAK2)/signal transducer and activator of transcription 3(STAT3)pathway in rats with dietinduced obesity(DIO).Methods Forty male SD rats were randomly divided into 10 in normal group and 30 in modeling group.A high-fat diet was used to establish the DIO rat model.After successful modeling,the modeled rats were randomly divided into the model group,the acupoint catgut embedding group and the acupoint catgut embedding+AG490(JAK2/STAT3 pathway blocker)group,with 10 rats in each group.The acupoint catgut embedding group and the acupoint catgut embedding+AG490 group were embedded on day(s)1,8,15 and 22 after successful modeling,the acupoints were selected from the Zhongwan(RN12),Shuidao(ST28),Tianshu(ST25),Pishu(BL20),Weishu(BL21),Sanjiaoshu(BL22)with a total of 4 treatments,and the acupoint catgut embedding+AG490 group was injected intraperitoneally with 1 mg/kg of AG490 every day during the treatment period;the normal group and the model group were only grasped and fixed.Body mass was measured before and after treatment.Lipid metabolism indexes of triglyceride(TG),total cholesterol(TC),low-density lipoprotein cholesterol(LDL-C),high-density lipoprotein cholesterol(HDL-C),and serum leptin levels were measured after treatment,and the mRNA expressions of hypothalamus LepR,JAK2 and STAT3 were detected by real-time quantitative polymerase chain reaction(RT-PCR),and the protein expressions of hypothalamus LepR,JAK2 and STAT3 were detected by Western Blot.Results Before treatment,compared with the normal group,the body mass of the model group,the acupoint catgut embedding group,and the acupoint catgut embedding+AG490 group were all elevated(P<0.01),and compared with the model group,there was no significant difference in the body mass between the acupoint catgut embedding group and the acupoint catgut embedding+AG490 group(P>0.05).After treatment,compared with the normal group,body mass,leptin and TG,TC,LDL-C levels were increased,and mRNA and protein expression levels of LepR,JAK2,STAT3 were decreased in the model group(all P<0.01);compared with the model group,body mass,leptin and TG,TC,LDL-C levels were decreased in the acupoint catgut embedding group,and mRNA and protein levels of LepR,JAK2,STAT3 were increased in the acupoint catgut embedding+AG490 group(all P<0.01);compared with the acupoint catgut embedding+AG490 group,the body mass,leptin and TG,TC,LDL-C levels were decreased,and mRNA and protein levels of LepR,JAK2,STAT3 were increased in the acupoint catgut embedding group(P<0.05 or P<0.01).Conclusion Acupoint catgut embedding has a good effect on weight loss and lipid reduction in DIO rats,and its central mechanism may be related to the down-regulation of serum leptin level and activation of hypothalamic LepR-mediated JAK2/STAT3 pathway.