高山绿茶提取物对小鼠高胆固醇血症及脂肪肝的防治作用及其机制

Prevention of high-mountain green tea extract on hypercholesterolemia and fatty liver in mice

目的研究高山绿茶提取物(GTE)对小鼠高胆固醇血症及脂肪肝的影响及其作用机制。方法C57 BL/6小鼠随机分为正常对照组、高脂饲料喂养模型组及其加用GTE防治的低、中、高剂量组。喂养28 d后,检测血脂、肝功、肝脏氧化指标,肝脏行HE染色、油红O染色,检测小肠中尼曼-匹克C1样蛋白1(NPC1L1)和甾醇反应元件结合蛋白2(SREBP2)的mRNA和蛋白水平。结果GTE可剂量依赖性地改善小鼠高胆固醇血症、肝功、病理学改变、肝脏氧化损伤与脂质沉积,并降低小肠NPC1L1和SREBP2的mRNA和蛋白水平。结论GTE可预防小鼠高胆固醇血症及脂肪肝,其作用机制与下调小肠NPC1L1和SREBP2基因的表达、减少胆固醇的吸收相关。

OBJECTIVE hypercholesterolemia and fatty liver in mice.METHODS C57 BL/6 mice were randomly divided into normal control group,high-fat fed model group,and low dose,medium dose and high dose of GTE treated groups.After feeding of 28 days,the serum lipid,liver function and liver oxidative indexes of mice were detected,and the liver was examined by HE staining and Oil red O staining.Then,western blot and RT-qPCR were used to deteet the protein and Niemann-Pick C1-like 1(NPC1 L1)and sterol response element-binding protein 2(SREBP2)in the small intestine of mice.RESULTS GTE dose-dependently improved the dyslipidemia,liver function indexes,hepatic histopathology,hepatic oxidation indexes and hepatic lipid deposition,and GTE could also inhibited the protein and mRNA expression levels of NPC1 L1 and SREBP2 in the small intestine of hypercholesterolemia mouse model.CONCLUSION GTE could prevent hypercholesterolemia and fatty liver in mice,where the mechanism might be associated with the downregulation of NPC1 L1 and SREBP2 gene expression in the small intestine to reduce the absorption of cholesterol.