瓜子金基于HMG-COA/SREBP/LXRa通路的LO2细胞脂代谢研究

Study on Lipid Metabolism in LO2 based on HMG-COA/SREBP/LXRa Pathway by Polygala japonica Houtt

目的:探索瓜子金不同萃取部位在体外对人正常肝细胞(LO2)脂代谢的影响.方法:建立LO2高胆固醇、高甘油三酯模型,利用酶标仪比色法考察不同萃取部位对LO2细胞内胆固醇、甘油三酯的影响,利用Western-Blot考察不同萃取部位对HMG-COA还原酶、SREBP-2、LXRa蛋白表达的影响.结果:二氯甲烷部位(Ⅱ)和正丁醇部位(Ⅲ)能显著降低LO2细胞中胆固醇及甘油三酯的含量(P<0.05);进一步的Western-Blot结果表明,在高胆固醇模型中,Ⅱ部位和Ⅲ部位均可显著降低细胞中HMG-COA还原酶蛋白的表达,Ⅱ部位对SREBP-2蛋白和LXRa的影响无显著性差异,Ⅲ部位则表现出降低SREBP-2而升高LXRa的作用;在高甘油三酯模型中,Ⅱ部位和Ⅲ部位均对HMG-COA无影响,但均可降低SREBP-2的表达,另Ⅱ部位降低LXRa的表达呈显著性差异.结论:瓜子金二氯甲烷部位和正丁醇部位可干预LO2细胞的胆固醇、甘油三酯代谢,并且可能是通过调节SREBP-2/HMG-COA/LXRa的表达而实现的.

Objective:To investigate the effect of different polar part from Polygala japonica Houtt,on LO2 lipid metabolism in vitro.Methods:To establish LO2 model of high cholesterol and high triglyceride,and investigate the effect of different polar part on them by enzyme standard colorimetric method.The effects of different extraction sites on the expression of HMG-COA,SREBP-2 and LXRa were studied by Western-Blot.Results:The contents of cholesterol and triglyceride in the LO2 were significantly decreased by dichloromethane(Ⅱ)and n-butyl alcohol(Ⅲ)fraction.Further results are shown by Western-Blot that,based on the high cholesterol model,ⅡandⅢcan significantly reduce the cell HMG-COA reductase protein expression,but the effects ofⅡon SREBP-2 and LXRa were not significantly different,and the difference is,Ⅲshowed the effect of decreasing SREBP-2 and increasing LXRa.Based on the high triglyceride cell model,there was no significant difference in the effect ofⅡandⅢon HMG-COA,but both of them could reduce the expression of SREBP-2,and in addition,the expression of LXRa was significantly decreased byⅡ.Conclusion:Dichloromethane and n-butyl alcohol fraction of Polygala japonica Houtt,can interfere with the LO2 cell cholesterol and triglyceride metabolism.And possibly,they achieve these goals by modulating the pathway of SREBP-2/HMG-COA/LXRa.