紫甘薯花色苷通过抑制仓鼠胆固醇内源合成降低血清胆固醇水平

Purple sweet potato anthocyanins reducing serum TC by suppression endogenous cholesterol synthesis in hamster

研究紫甘薯花色苷对高脂高胆固醇膳食喂饲仓鼠血清胆固醇水平及肝脏中胆固醇代谢相关基因表达水平的影响。50只仓鼠随机分5组(正常组,模型组,2g/kg,4g/kg,8g/kg紫甘薯花色苷组),测定血清中总胆固醇(TC),甘油三酯(TG),高密度脂蛋白胆固醇(HDL-C)水平,荧光定量聚合酶链反应(Real-timePCR,RT-PCR)检测肝脏中胆固醇代谢相关基因的表达水平。模型组TC,TG,HDL-C水平较正常组极显著升高(P<0.01),添加紫甘薯花色苷后血清TC水平呈下降趋势,且8g/kg组有显著性(P<0.05);Realtime PCR分析显示,紫甘薯花色苷下调肝脏中3-羟基-3-甲基戊二酰基-Co A还原酶(HMG-Co A-R)基因的表达,上调肝X受体α(LXRα)基因的表达。紫甘薯花色苷具有降胆固醇作用,其机制可能是通过抑制肝脏中胆固醇内源合成实现的。

the effects of purple sweet potato anthocyanins on serum cholesterol level and hepatic cholesterol- regulating genes expression in hamsters fed with a high fat and high cholesterol diet was invesitgated. In the experiment, 50 hamsters were divided into 5 groups randomly （normal, model, 2g/kg, 4g/kg, 8g/kg purple sweet potato anthocyanins）. Serum total cholesterol （TC）, triacylglycerol （TG） and high density lipoprotein cholesterol （HDL-C） were measured. The mRNA expressions of key enzymes related to cholesterol metabolism were measured by Real time-PCR （RT-PCR） . Serum TC, TG, HDL-C were increased in model group compared with those in nomal hamsters （P 〈 0.01）, while TC was decreased in 8g/kg purple sweet potato anthocyanins group compared with the control group. RT-PCR assay results showed that mRNA expression of 3-hydroxy-3-methylglutaryl-CoA reductase （HMG-CoA-R） was decreased while liver X receptor （LXRa） was up-regulated in liver. The mechanism underlying the cholesterol-lowering activity of purple sweet potato anthocyanins was mediated most likely through reducing endogenous synthesis of cholesterol in liver.