银杏叶提取物改善高脂血症大鼠肝损伤的机制

Mechanism of Ginkgo Biloba Extract Improves Liver Injury of Hyperlipidemia Rat

为了研究银杏叶提取物(GBE)对高脂血症大鼠肝损伤的改善作用及机制,用不同浓度梯度的酒精和高糖高脂饲料建立高脂血症大鼠模型,造模同时用GBE(25 mg/kg、50 mg/kg、100 mg/kg)进行灌胃干预.称量大鼠肝重量,计算各组大鼠肝指数,利用生物显微技术观察肝脏组织结构的变化,全自动生化分析仪检测血清中甘油三酯(TG)、谷丙转氨酶(ALT)、谷草转氨酶(AST)水平及游离脂肪酸(FFA)含量,酶联免疫吸附(ELISA)法测定脂肪甘油三酯水解酶(ATGL)和激素敏感性甘油三酯脂肪酶(HSL)水平,实时荧光定量PCR和Western blot检测肝组织过氧化物酶体增殖物激活受体γ(PPARγ)、固醇调节元件结合蛋白-1c(SREBP-1c)、腺苷酸活化蛋白激酶(p-AMPK)、蛋白磷酸酶1(PP1)、DNA依赖的蛋白激酶(DNA-PK)、上游刺激因子1(USF1)mRNA水平和蛋白含量.结果显示,与模型组相比,经GBE干预后,大鼠肝指数显著降低(P<0.05,P<0.01),肝脏损伤程度明显减轻,血清TG、ALT、AST水平及FFA含量显著降低(P<0.05,P<0.01),脂肪ATGL含量明显升高(P<0.05,P<0.01),脂肪HSL含量明显降低(P<0.05,P<0.01),肝脏PP1、DNA-PK、USF1、PPARγmRNA水平和蛋白含量明显升高(P<0.05,P<0.01),肝脏AMPK、SREBP-1 cmRNA水平和蛋白表达下降(P<0.05,P<0.01).结果表明,GBE能降低高脂血症模型大鼠血脂水平,改善肝功能,减轻肝脏损伤,其作用机制可能通过调节PPARγ-HSL/ATGL、PP1-DNA-PK-USF1和AMPK/SREBP-1c信号通路来实现对高脂血症大鼠的保护作用.

In order to explore the improvement effect of extracts from ginkgo biloba extract(GBE)on liver injure of hyperlipidemia rat and possible regulation mechanism.A hyperlipidemia rat model was established by giving different concentrations of alcohol and feeding with high-sugar and fat diets.While being modeled,the rats were given GBE at doses of 25 mg/kg,50 mg/kg or 100 mg/kg by intragastric administration.The wet liver weight of rats was measured to calculate the liver index.The changes of liver histological structure were observed by bio-microscopy.The levels of triglyceride(TG),alanine aminotransferase(ALT),aspartate aminotransferase(AST)and free fatty acid(FFA)in serum were determined by automatic biochemistry analyzer.Additionally,it was detected that the levels of adipose tiglyceride lipase(ATGL)and hormone-sensitive triglyceride lipase(HSL)by ELISA.Quantitative PCR and western blot were used to detect mRNA and protein content changes of hepatic peroxisome proliferators-activated receptors(PPARγ),sterol regulatory element-binding protein 1c(SREBP-1c),adenine monophosphate activated protein kinase(AMPK),protein phosphatase 1(PP1),DNA-dependent protein kinase(DNA-PK)and upstream stimulating factor 1(USF1).Compared with the model group,the liver index decreased significantly(P<0.05,P<0.01),hepatic pathological changes were meliorated.GBE administration could obviously decrease TG,ALT,AST and FFA levels in serum and liver to varying degrees,significantly activate fat ATGL content,and significantly reduce the content of fat HSL(P<0.05,P<0.01),increase mRNA levels and protein contents of PP1,DNA-PK,USF1 and PPARγ(P<0.05,P<0.01),meanwhile reduce mRNA levels and protein contents of AMPK and SREBP-1c in liver(P<0.05,P<0.01).The results indicate that GBE could decrease blood lipid level,improve liver function and reduce liver injure in hyperlipidemia model rats.Its mechanism may be related to regulation of PPARγ-HSL/ATGL,PP1-DNA-PK-USF1 and AMPK/SREBP-1c signaling pathway.