替米沙坦诱导大鼠肝细胞自噬促进肝脏胆固醇代谢的机制研究

目的探讨替米沙坦诱导大鼠肝细胞自噬对肝脏胆固醇代谢的影响及作用机制。方法将肝脏原代细胞分为正常对照组(Con)、替米沙坦1μmol/L组(Tel 1组)、替米沙坦3μmol/L组(Tel 3组)、替米沙坦10μmol/L组(Tel 10组)、替米沙坦10μmol/L联合PPARγ抑制剂GW 9662组(Tel+G组)。Tel 1、Tel 3、Tel 10组分别按1、3、10μmol/L浓度加入替米沙坦,Tel+G组加入10μmol/L替米沙坦及PPARγ抑制剂GW9662,培养24 h。检测肝细胞胆固醇浓度,Western blot法检测微管相关蛋白轻链3(LC3)、自噬蛋白区域(Beclin-1)、腺苷酸活化蛋白激酶(AMPK)、雷帕霉素靶分子(mTOR)表达水平。结果 Tel 3、Tel 10组胆固醇水平低于Con、Tel 1组(P<0.05)。Tel 1、Tel 3、Tel 10组LC3Ⅱ/Ⅰ比值、Beclin-1蛋白水平依次升高(P<0.05)。与Con、Tel 1组比较,Tel 3、Tel 10组p-AMPK/AMPK蛋白比值升高(P<0.05),p-mTOR/mTOR蛋白比值降低(P<0.05)。与Tel 10组比较,Tel+G组胆固醇水平、p-mTOR/mTOR蛋白比值升高(P<0.05),LC3II/I比值、p-AMPK/AMPK蛋白水平降低(P<0.05)。结论替米沙坦可通过诱导大鼠肝细胞自噬影响肝脏细胞胆固醇代谢,其机制可能与激活AMPK/mTOR途径和上调PPARγ有关。

Mechanism of Telmisartan-induced autophagy and promoting effect in cholesterol metabolism in rat hepatocytes

Objective To investigate the effect and mechanism of Telmisartan-induced hepatocyte autophagy on cholesterol metabolism in rat liver.Methods The liver cells were divided into normal control group(Con),Telmisartan 1 μmol/L group(Tel 1 group),Telmisartan 3 μmol/L group(Tel 3 group),Telmisartan 10 μmol/L group(Tel 10 group),Telmisartan 10 μmol/L+PPARγ inhibitor GW 9662 group(Tel+G group).Telmisartan was added into Tel 1,Tel 3 and Tel 10 group according to the concentration gradient of 1 μmol/L,3 μmol/L and 10 μmol/L,respectively.Telmisartan of 10 μmol/L and PPARγ inhibitor GW9662 were added into Tel+G group.After 24 hours of culture,the level of cholesterol in hepatocytes was detected.The expression levels of light chain-3(LC3),Beclin-1,AMP-activated protein kinase(AMPK) and mammalian target of rapamycin(mTOR) in liver cells were detected by Western blot.Results The cholesterol level was lower in Tel 3 and Tel 10 group than in control and Tel 1 group CP<0.05).The LC3 Ⅱ/Ⅰ ratio and expression level of Beclin-1 increased successively in Tel 1,Tel 3 and Tel 10 group(P<0.05).Compared with control and Tel 1 group,The p-AMPK/AMPK protein ratio increased,while the p-mTOR/mTOR protein ratio decreased in Tel 3 and Tel 10 group(P<0.05).Compared with Tel 10 group,the cholesterol concentration and p-mTOR/mTOR protein ratio increased CP<0.05), the LC3 Ⅱ/Ⅰ ratio and p-AMPK/AMPK protein level decreased in Tel+G group(P<0.05).Conclusion Telmisartan can affect cholesterol metabolism in liver cells of rats by inducing autophagy, and its mechanism may be related to the activation of AMPK/mTOR pathway and the up-regulation of PPARγ.