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本文研究肝X受体(LXR)激动剂对apoE基因敲除小鼠NPC1表达的影响.52只雄性apoE基因敲除小鼠被随机分成4组:(a)基础组(baseline group,n=10);(b)对照组(control group,n=14);(c)LXR激动剂治疗组(treatment group,n=14);(d)LXR激动剂预防组(prevention group,n=14).各组小鼠均被给予高脂/高胆固醇饲料喂养;基础组小鼠被赋形剂灌胃处理8周;对照组小鼠被赋形剂灌胃处理14周;LXR激动剂治疗组小鼠在前8周被赋形剂灌胃处理,后6周被T0901317灌胃处理;LXR激动剂预防组小鼠被T0901317灌胃处理14周.采用实时定量PCR,Western blot和免疫组织化学方法分别检测组织中NPC1 mRNA和蛋白质的表达;采用酶法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)、低密度脂蛋白胆固醇(LDL-C)、载脂蛋白A-Ⅰ(ApoA-Ⅰ)和载脂蛋白B(ApoB)含量.另外,我们采用RNA干扰技术沉默人THP-1巨噬细胞NPC1基因表达,并将细胞诱导成泡沫细胞,检测T0901317对该细胞胆固醇流出的影响.结果显示,LXR激动剂治疗组和预防组小鼠的血浆TC,TG,HDL-C和ApoA-Ⅰ水平都较对照组明显增高(P<0.05);LXR激动剂治疗组和预防组小鼠的主动脉粥样硬化斑块和脂质条纹明显少于对照组(P<0.05),其中治疗组减少了58.3%,预防组减少了64.2%;LXR激动剂治疗组和预防组小鼠的小肠组织、肝脏组织和主动脉NPC1表达上调(P<0.05);和正常THP-1巨噬细胞源性泡沫细胞比较,RNA干扰组胆固醇流出明显减少,T0901317处理组胆固醇流出明显增加.总之,LXR激动剂T0901317能减轻高脂高胆固醇饲料喂养的apoE基因敲除小鼠动脉粥样硬化病变程度并上调肝脏组织、小肠组织和主动脉NPC1的表达,NPC1基因沉默能使细胞胆固醇流出减少。
The aim of this study was to investigate the effect of liver X receptor (LXR) agonist on NPC1 expression in apoE knockout mice. Fifty-two male apoE knockout mice were randomly divided into 4 groups: (a) baseline group (n = 10) ; (b) control group (n = 14); (c) LXR agonist treatment group (n = 14); (d) LXR agonist prevention group (n = 14). The mice in each group were fed with high-fat / high-cholesterol diet. The mice in the basal group were orally administered with the vehicle for 8 weeks. The mice in the control group were orally administered with the vehicle for 14 weeks. The mice in the LXR-treated group The rats in the LXR agonist group were intragastrically treated with T0901317 for 14 weeks by real-time quantitative PCR, Western blot and immunohistochemistry respectively The expression of NPC1 mRNA and protein were detected by enzyme-linked immunosorbent assay (ELISA). The levels of total cholesterol (TC), triglyceride (TG), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL- In addition, we used RNA interference to silence the expression of NPC1 gene in human THP-1 macrophages and induced the cells to become vacuolar The results showed that the levels of TC, TG, HDL-C and ApoA-I in the LXR-treated and prophylaxis groups were significantly higher than those in the control group (P <0.05) ; LXR agonist treatment group and prevention group mice aortic atherosclerosis plaque and lipid streaks were significantly less than the control group (P <0.05), in which the treatment group decreased 58.3%, prevention group decreased 64.2%; LXR Compared with normal THP-1 macrophage-derived foam cells, the expression of NPC1 in liver tissue and aorta was upregulated (P <0.05), and the efflux of cholesterol in RNA interference group was significantly decreased. T0901317 In conclusion, LXR agonist T0901317 can reduce the degree of atherosclerosis and up-regulate the expression of NPC1 in liver tissue, small intestine and aorta of apoE knockout mice fed with high fat and high cholesterol diet, and NPC1 gene Silence can reduce cellular cholesterol efflux.