二氢杨梅素上调SIRT1信号通路改善HepG2细胞甘油三酯蓄积

Dihydromyricetin improves triglyceride accumulation in HepG2 cells by regulating SIRT1 signaling pathway

目的探究二氢杨梅素(dihydromyricetin,DHM)对肝细胞脂质代谢的影响及其与SIRT1信号通路的关系。方法 0.2 mmol/L棕榈酸(palmitic acid,PA)处理HepG2细胞24 h,诱导为脂肪变性肝细胞模型,再用0、5、10、20μmol/L DHM及20μmol/L DHM+2μmol/L SIRT1抑制剂(EX527)分别干预24 h,CCK-8检测细胞增殖活性,油红0染色检测细胞脂滴形成情况,酶偶联比色法检测甘油三酯(triglyceride,TG)含量,蛋白免疫印迹法检测沉默信息调节因子1(silent information regulator 1,SIRT1)、腺苷酸活化蛋白激酶(adenosine monophosphate activated protein kinase,AMPK)、固醇调节元件结合蛋白1c(sterol regulatory element binding protein-1,SREBP-1c)、脂肪酸合成酶(fatty acid synthetase,FAS)、乙酰辅酶A羧化酶(acetyl-Co A carboxylase,ACC)的表达。结果 0.2 mmol/L PA和5、10、20μmol/L DHM对细胞增殖活力没有显著影响(P>0.05);5、10、20μmol/L DHM处理后明显减少脂肪变性的HepG2细胞脂滴蓄积和甘油三酯含量(P<0.01),增加磷酸化的AMPK(p-AMPK)和SIRT1的表达水平,并且降低脂质合成相关基因SREBP-1c、FAS、磷酸化的ACC(p-ACC)的蛋白表达,SIRT1抑制剂能显著增加脂肪变性的HepG2细胞的甘油三酯含量(P<0.01),削弱DHM对脂肪变性HepG2细胞SREBP-1c、FAS、P-ACC表达的抑制作用。结论 DHM通过上调脂肪变性HepG2细胞SIRT1信号通路改善肝细胞脂肪变性。

Objective To determine the effect of dihydromyricetin （DHM） on lipid metabolism in hepatic cells and its relationship with silent information regulator 1 （SIRT1） signaling pathway. Methods HepG2 cells were treated by 0.2 mmol/L palmitic acid （PA） for 24 h to establish a model of hepatic steatosis, and then followed by the treatment of 0, 5, 10 and 20 μmol/L DHM or 20 μmol/L DHM plus 2 μmol/L EX527 （SIRT1 inhibitor） for 24 h.CCK-8 assay was used to detect the cell viability, oil Red O staining was employed to detect the intracellular lipid droplets, enzyme-coupled colorimetric assay was adopted to measure triglyceride （TG） content, and Western blotting was used to detect the protein expression of SIRT1, adenosine monophosphate activated protein kinase （AMPK）, sterol regulatory element binding protein-1 （SREBP-1c）, fatty acid synthetase （FAS） and acetyl-CoA carboxylase （ACC）. Results The results indicated that 0.2 mmol/L PA as well as 5, 10 and 20 μmol/L DHM had no significant effect on the proliferation of HepG2 cells （P〉0.05）, while 5, 10 and 20 μmol/L DHM significantly reduced the accumulation of lipid droplets and level of TG in HepG2 cells, increased the protein expression levels of P-AMPK and SIRT1, and at the same time, reduced the protein levels of SREBP-1c, FAS and p-ACC. SIRT1 inhibitor, EX527, significantly increased the TG level （P〈0.01）, and weakened the reducing effect of DHM on the levels of SREBP-1c, FAS and p-ACC in HepG2 cells. Conclusion DHM improves hepatocyte fatty degeneration by up-regulating SIRT1 signaling pathway.