电针对腹型肥胖大鼠肝脏脂代谢及Sirt1/PPARγ通路的影响

Impact of electroacupuncture on liver lipid metabolism and hepatic Sirt1 and PPARγ expression in abdominal obese rats

目的:探讨电针对高脂饮食诱导的腹型肥胖大鼠肝脏脂代谢及沉默信息调节因子1(Sirts1)、过氧化物酶体增殖物激活受体γ(PPARγ)表达的影响。方法:SD雄性大鼠,随机分为空白组6只,造模组29只。造模组大鼠高脂饮食喂养12周,建立腹型肥胖模型。造模成功的12只腹型肥胖大鼠,随机分为模型组6只、针刺组6只,针刺组大鼠电针双侧"带脉"穴,2Hz/15Hz疏密波,电流强度1.5mA,每次20min,隔日1次,干预8周。每周测量体质量、腹围。针刺8周末,采用全自动生化仪检测血清总胆固醇(TC)、甘油三酯(TG)、谷丙转氨酶(ALT)、谷草转氨酶(AST),油红"O"染色法观察肝脏病理形态学变化,荧光定量PCR法检测肝组织Sirt1和PPARγ mRNA的表达,Western blot法检测肝组织Sirt1和PPARγ蛋白的表达水平。结果:与正常组比较,模型组的体质量、腹围明显增加(P<0.001,P<0.01),血清TC、TG、ALT、AST含量明显升高(P<0.01),肝脏脂质堆积明显增加,Sirt1 mRNA及蛋白的表达明显下降(P<0.05,P<0.01),PPARγ mRNA及蛋白的表达明显增加(P<0.01,P<0.05);与模型组比较,针刺组大鼠体质量、腹围明显减小(P<0.05,P<0.01),TC、TG、ALT、AST明显降低(P<0.05),肝脏脂质堆积明显减轻,肝组织Sirt1 mRNA及蛋白的表达显著增加(P<0.001,P<0.05),PPARγ mRNA及蛋白的表达明显降低(P<0.05,P<0.01)。结论:针刺可改善腹型肥胖大鼠肝脏脂质代谢,其机制可能与上调Sirt1、下调PPARγ的表达相关。

Objective To observe the impact of electroacupuncture(EA)on liver lipid metabolism and expression of hepatic sirtuin 1(Sirt1)and peroxisome proliferator activated receptorγ(PPARγ)of abdominal obese rats induced by high-fat diet.Methods Eighteen male SD rats were divided into blank control,model and EA groups(n=6 per group).The abdominal obesity model was established by feeding the rats with high-fat diet for 12 weeks.EA(2 Hz/15 Hz,1.5 mA)was applied to bilateral"Daimai"(GB26)for 20 min every time,once every other day for 8 weeks.Rats of the model group were also restrained for 20 min.The body mass and abdominal circumference were measured every week,and the contents of serum cholesterol(TC),triglyceride(TG),alanine transaminase(ALT),aspartate aminotransferase(AST)were detected by using an automated biochemical analyzer.Histopathological changes of the liver tissues were observed under microscope after oil red "O"staining.The expression of hepatic Sirt1 and PPARγ mRNAs and proteins were detected using quantitative real time PCR and Western blot,separately.Results After modeling,the body weight and abdominal circumference,and serum TC,TG,ALT and AST contents,and expression of hepatic PPARγ mRNA and protein were significantly increased(P<0.001,P<0.01,P<0.05),and the expression levels of hepatic Sirt1 mRNA and protein obviously down-regulated(P <0.05,P <0.01)in the model group.Following EA intervention,the increased body weight and abdominal circumference,and serum TC,TG,ALT and AST contents,and hepatic PPARγ mRNA and protein expression were remarkably suppressed(P<0.05,P<0.01),and the decreased hepatic Sirt1 mRNA and protein were remarkably up-regulated(P<0.001,P<0.05).The lipid droplets in hepatocytes were reduced in the EA group relevant to the model group.Conclusion EA intervention can significantly improve the liver lipid metabolism of abdominal obese rats,which is possibly related with its effect in up-regulating the expression of hepatic Sirt1 mRNA and protein,and in down-regulating the expression of hepatic PPARγ mRNA and protein.