二氢杨梅素经激活AMPK-PGC1α-Sirt1信号通路促进高脂饮食诱导的肥胖小鼠肩胛下脂肪组织棕色化

Dihydromyricetin promoted browning of subscapular adipose tissues in obese mice fed with high-fat diet via activating AMPK-PGC1α-Sirt1 signaling pathway

目的观察二氢杨梅素(DHM)对高脂饮食诱导的肥胖小鼠肩胛下脂肪组织棕色化的影响,并阐明其机制。方法C57bl/6j小鼠采用普通饲料和高脂饲料喂养,同时分别用或不用低剂量(125 mg·kg^-1·d^-1)或高剂量(250 mg·kg^-1·d^-1)的DHM处理16W。实验期间每4周测一次小鼠体质量,16周后小鼠空腹过夜测空腹血糖,接着处死小鼠,测量体长后算出Lee’s指数,随后取肩胛下脂肪组织,一部分HE染色观察脂肪细胞形态,另一部分通过实时定量PCR和蛋白质免疫印迹法检测肩胛下脂肪组织:解偶联蛋白1(UCP1)、锌指转录因子PR结构域包含子16(Prdm16)、腺苷酸活化蛋白激酶(AMPK)、过氧化物酶体增殖激活受体γ辅助激活因子α(PGC1α)和沉默信息调节因子1(Sirt1)的基因和蛋白表达。结果与正常对照组(ND组)相比,高脂饮食组(HFD组)小鼠体质量明显增加,说明肥胖小鼠模型复制成功;此外,HFD组小鼠血糖、Lee’s指数和肩胛下脂肪组织脂肪细胞直径增加,UCP1、Prdm16、AMPK、PGC1α和Sirt1基因和蛋白表达降低;DHM可逆转HFD小鼠上述指标的改变,但DHM不影响正常小鼠这些指标。结论二氢杨梅素可能经激活AMPK-PGC1α-Sirt1信号通路促进高脂饮食诱导的肥胖小鼠肩胛下脂肪组织棕色化。

Aim To observe the effect of dihydromyricetin(DHM)on the browning of subscapular adipose tissues in the high-fat diet fed obese mice,and clarify the mechanism.Methods C57BL/6J mice were fed with normal and high-fat diet,and were treated with or without low dose(125 mg·kg^-1·d^-1)or high dose(250 mg·kg^-1·d^-1)DHM for 16W.The body mass of mice was measured every four weeks during the experiment.After 16 weeks,the mice were fasted overnight.Blood samples were taken for fasting blood glucose.The mice were then sacrificed and the body length measured.The Lee’s index was calculated.The size of the subscapular adipocytes was observed by HE staining.The mRNA and protein expression of uncoupling protein 1(UCP1),PR domain containing 16(Prdm16),adenylate-activated protein kinase(AMPK),peroxisome proliferator-activated receptor gamma-assisted activator alpha(PGC1α)and silencing signal regulator 1(Sirt1)were assessed by real-time quantitative PCR and Western blot assay.Results Compared with normal control group(ND group),the body mass of mice in high-fat diet group(HFD group)significantly increased,suggesting that the obese mice model was successfully replicated.In addition,blood glucose,Lee’s index and the fat cell diameter of the subscapular adipose tissues in HFD group all significantly increased,while the mRNA and protein expression of UCP1,Prdm16,AMPK,PGC1αand Sirt1 significantly decreased.DHM markedly reversed the changes of the above indexes of HFD mice,but DHM did not significantly affect the above indexes of normal mice.Conclusions Dihydromyricetin promotes the browning of subscapular adipose tissues in mice fed with high-fat diet,which might be via activating AMPK-PGC1α-Sirt1 signaling pathway.