【作者】 常伟；

【导师】 周岐新；

【作者基本信息】 重庆医科大学 ， 药理学， 2008， 硕士

【摘要】 目的:研究小檗碱(berberine,Ber)对胆固醇代谢的影响,并探讨其可能的作用机制。方法:1. SD大鼠40只随机分为普食组(normal diet,ND),高脂饲料组(high fat diet,HFD),高脂饲料+洛伐他汀组(lovastatin,LD),高脂饲料+低剂量小檗碱干预组(berberine low dose diet,BLD),高脂饲料+高剂量小檗碱干预组(berberine high dose diet,BHD)。饲养18周后测定大鼠血中胆固醇(total cholesterol,TC)、高密度脂蛋白胆固醇(high densitylipoprotein cholesterol ,HDL-C)、低密度脂蛋白胆固醇(1ow densitylipoprotein cholesterol ,LDL-C)等血生化指标的含量。RT-PCR, Western blot分别检测各组大鼠肝脏胰岛素诱导基因2(Insulin-induced gene 2,Insig-2)mRNA和蛋白表达变化。2.RT-PCR,Western blot检测不同浓度(1、3、10、30、100μmol/L)Ber处理24 h后及3μmol/L Ber处理不同时间(0、12、24、48、72h)后HepG2细胞中Insig-2和VDR基因表达,并进行相关性分析。结果:1.Ber显著降低高脂模型大鼠的TC和LDL-C水平,同时显著升高大鼠血清HDL-C。2.低剂量Ber能显著增加高脂模型大鼠肝脏Insig-2基因mRNA和蛋白表达水平;高剂量Ber对Insig-2基因mRNA和蛋白表达影响不明显。3.Ber对HepG2细胞Insig-2和VDR基因表达呈双向调节作用:≤3μmol/L时呈浓度依赖性上调,>3μmol/L表达值则下降,两者的变化具有相关性(r=0.753,p<0.01);时-效关系研究显示,3μmol/L Ber在48 h作用时间内呈时间依赖性上调Insig-2和VDR基因的表达,两者的变化具有相关性(r=0.922,p<0.01)。结论:Ber具有明显调血脂作用,其机制可能与其上调VDR的表达,进而上调Insig-2基因表达,从而抑制肝脏中胆固醇的合成代谢有关。更多还原

【Abstract】 Objective:To investigate the effects of berberine (Ber) on cholesterol metabolism and its mechanism。Methods:1. SD rats were randomly divided into 5 groups: normal diet + pretreatment of solvent (ND); high-fat and high-cholesterol diet + pretreatment of solvent (HFD); high-fat and high-cholesterol diet + pretreatments of either lovastatin(LD) orBer low dose (BLD) and Ber high dose (BHD). The levels of total cholesterol(TC),low density lipoprotein cholesterol (LDL-C) , and high density lipoprotein cholesterol(HDL-C) in blood were detected eighteen weeks after rats were fed with high-fat and high-cholesterol diet and and pretreated with either solvent or drugs. The mRNA and protein expressions of Insulin-induced gene 2(Insig-2) in rat liver were quantified by RT-PCR and Western blot。2. HepG2 cells were incubated with Ber at different concentrations (1, 3, 10, 30, 100μmol/L), or incubated with 3μmol/L Ber for various times (0, 12, 24, 48, 72 h). The gene expressions of Insig-2 and VDR from HepG2 cells treated by Ber were quantified by RT-PCR and Western blot.Results:1. The blood levels of TC and LDL-C were significantly lower in Ber groups than those in HFD, except HDL-C level that was shown to clearly increase after rats were pretreatment with Ber.2.Low dose Ber pretreatment significantly increased Insig-2 gene mRNA and protein expressions from rat liver but high dose Ber pretreatment had no significantly effects on Insig-2 gene expression.3.24 h after exposure to gradient concentrations of Ber, the gene expressions of Insig-2 and VDR in HepG2 cells showed a dualistic changes:the maximum values occurred at 3μmol/L, then the values declined gradually. The pretreatment with 3μmol/L Ber for different time made the gene expressions of Insig-2 and VDR significantly increased with the peak value at 48 h;the relative coefficient between them was 0.922 (p<0.01).Conclusion:Ber can significantly decrease the levels of hyperlidemia, the mechanism of which may be related to elevating expressions of Insig-2 and VDR genes in liver. As a result the cholesterol synthesis of liver was inhibited.更多还原