苜蓿皂苷对高脂血症大鼠胆固醇代谢及其相关基因表达的影响

本文旨在探讨苜蓿皂苷对高脂血症大鼠胆固醇代谢及肝脏组织中胆固醇7α-羟化酶( CYP7 A1)、低密度脂蛋白受体(LDL-R)基因表达的影响.取雄性健康SD大鼠40只,随机分为4组,分别为:正常对照组、高脂模型组、苜蓿皂苷预防组和苜蓿皂苷治疗组,每组10只.正常对照组饲喂基础饲粮,其余3组均饲喂高脂饲粮,其中苜蓿皂苷预防组从第1周开始灌胃240 mg/kg苜蓿皂苷,苜蓿皂苷治疗组从第5周开始灌胃240 mg/kg苜蓿皂苷,试验期共8周.测定试验大鼠体重、肝脏系数、血脂水平和肝脏病理变化情况,并采用酶联免疫法和实时荧光定量PCR技术分别检测大鼠肝脏CYP7A1和LDL-R的蛋白和mRNA表达结果.结果表明:1)和高脂模型组相比,苜蓿皂苷极显著降低预防组大鼠体重及预防组和治疗组血清总胆固醇及低密度脂蛋白胆固醇含量(P＜0.01),同时改善肝脏脂化程度.2)苜蓿皂苷预防组和治疗组CYP7 A1和LDL-R的蛋白和mRNA表达量极显著高于高脂模型组(P＜0.01).结果提示,苜蓿皂苷通过促进肝脏CYP7A1和LDL-R的表达,增强肝脏胆固醇的排泄,发挥其对高脂血症的预防和治疗作用.

Effects of Alfalfa Saponins on Cholesterol Metabolism and Its Related Gene Expression in Hyperlipidemic Rats

To investigate the effects of alfalfa saponins on cholesterol metabolism and the gene expression of cholesterol 7α-hydroxylase(CYP7Al) and low density lipoprotein receptor(LDL-R) in the liver of hyperlipidemic rats,forty healthy male SD rats were randomly divided into four groups: normal control group,hyperlipidemic model group,alfalfa saponins prevention group and alfalfa saponins treatment group.The rats in the normal control group were fed a basal diet,and the ones in other three groups were all fed high-fat diets.The experimental period was eight weeks.Alfalfa saponins(240 mg/kg) were administered to prevention group from the first week and treatment group from the fifth week by gavage.The body weight,liver index and serum lipid levels of rats were detected.As well as,livers were taken for pathological examination.The protein and mRNA expression of CYP7Al and LDL-R were measured by enzyme linked immunosorbent assay and real-time PCR methods,respectively.The results showed as follows: 1) compared with the hyperlipidemic model group,body weight in the prevention group,contents of total cholesterol and low density lipoprotein cholestorol in prevention and treatment groups were significantly decreased by alfalfa saponins(P<0.01),and the fatty degeneration of liver was ameliorated by alfalfa saponins.2) The protein and mRNA expression of CYP7Al and LDL-R in prevention and treatment groups were significantly higher than those in the hyperlipidemic model group(P<0.01).In conclusion,alfalfa saponins can prevent and treat hyperlipidemia by increasing the expression of CYP7Al and LDL-R in liver,and by promoting the excretion of liver cholesterol.