瓜蒌薤白对高脂血症小鼠肝脏三酰甘油合成及SIRT1/AMPK通路的影响

Effect of Fructus Trichosanthis-Macrostem Onion on Hepatic Triglyceride Synthesis and the SIRT1/AMPK Pathway in Hyperlipidemia Mice

目的 观察瓜蒌薤白对高脂血症小鼠肝脏三酰甘油(triglyceride, TG)合成及沉默信息调节因子1(silent information regulator 1,SIRT1)/腺苷酸活化蛋白激酶(AMP-activated protein kinase, AMPK)通路的影响。方法 将40只高脂饲料喂养20周的载脂蛋白E基因敲除小鼠随机分为模型组,瓜蒌薤白低、中、高剂量组,阿托伐他汀组,每组8只;另设8只具有相同遗传背景的C57BL/6J小鼠作为空白组。酶法检测血清TG、总胆固醇(total cholesterol, TC)、低密度脂蛋白胆固醇(low-density lipoprotein cholesterol, LDL-C)、高密度脂蛋白胆固醇(high-density lipoprotein cholesterol, HDL-C)水平;ELISA及qRT-PCR法检测肝脏脂肪酸合成酶(fatty acid synthase, FAS)和乙酰辅酶A羧化酶(acetyl CoA carboxylase, ACC)含量及mRNA表达水平;Western blot及qRT-PCR法检测肝脏胆固醇调节元件结合蛋白1(sterol regulatory element-binding protein-1,SREBP-1)、碳水化合物反应元件结合蛋白(carbohydrate response element-binding protein, ChREBP)、SIRT1、AMPK蛋白及mRNA表达水平。结果 瓜蒌薤白降低血清TG、TC及LDL-C水平,升高血清HDL-C水平,降低肝脏TG合成酶FAS和ACC含量及mRNA表达水平,下调肝脏TG合成蛋白SREBP-1、ChREBP表达水平,显著上调SIRT1表达水平,下调AMPK表达水平。结论 瓜蒌薤白调节高脂血症小鼠血脂水平的机制可能与其激活SIRT1/AMPK通路,抑制肝脏TG合成相关蛋白及合成酶表达,抑制TG内源性合成有关。

Objective To investigate the effect of Fructus Trichosanthis-macrostem onion on hepatic triglyceride(TG)synthesis and the SIRT1/AMPK pathway in hyperlipidemia mice.Methods A total of 40 mice with apolipoprotein E gene knockout were given high-fat feed for 20 weeks and were then randomly divided into model group,atorvastatin group,and low-,middle-,and high-dose Fructus Trichosanthis-macrostem onion groups,and 8 C57BL/6J mice with the same genetic background were enrolled as blank group.The enzymatic method was used to measure the serum levels of total cholesterol(TC),low-density lipoprotein cholesterol(LDL-C),and high-density lipoprotein cholesterol(HDL-C);ELISA and qRT-PCR were used to measure the content and mRNA expression levels of fatty acid synthase(FAS)and acetyl-CoA carboxylase(ACC)in mouse liver;Western blot and qRT-PCR were used to measure the protein and mRNA expression levels of sterol regulatory element-binding protein-1(SREBP-1),carbohydrate response element-binding protein(ChREBP),silent information regulator 1(SIRT1),and AMP-activated protein kinase(AMPK)in mouse liver.Results Fructus Trichosanthis-macrostem onion reduced the serum levels of TG, TC, and LDL-C and increased the serum level of HDL-C. It also reduced the content and mRNA expression levels of the hepatic TG synthases FAS and ACC and downregulated the expression levels of the hepatic TG synthesis proteins SREBP-1 and ChREBP. Moreover, it significantly upregulated the expression level of SIRT1 and downregulated the expression level of AMPK. Conclusion Fructus Trichosanthis-macrostem onion can regulate blood lipid levels in hyperlipidemia mice possibly by activating the SIRT1/AMPK pathway and inhibiting the expression of proteins and synthases associated with hepatic TG synthesis and the endogenous synthesis of TG.