apoE/LDLR双基因突变小鼠肝脏脂代谢相关基因的表达研究

目的探讨载脂蛋白E和低密度脂蛋白受体双基因缺失（apoE^-/-/LDLR^-/-）小鼠肝脏脂代谢相关基因表达特征与动脉粥样硬化早期病变的关系及发生机制。方法应用RT-PCR技术检测apoE^-/-／LDLR^-/-与野生型小鼠肝脏脂代谢相关基因表达差异,并进行血生化指标检测及主动脉形态学观察。结果所检测的11个脂代谢相关基因中,apoE^-/-／LDLR^-/-小鼠与野生型小鼠相比,载脂蛋白B100和脂肪酸转运体（FAT／CD36）的mRNA水平从14天龄至3月龄均升高。载脂蛋白AⅣ、载脂蛋白AⅤmRNA水平分别于14天龄和3月龄时明显降低。载脂蛋白AⅠ、载脂蛋白F、过氧化物增殖物激活型受体α、肝X受体α、血管生成素样蛋白3、酰基辅酶A氧化酶1及肉碱棕榈酰转移酶ImRNA表达水平无明显差异。血清总胆固醇、总甘油三酯和低密度脂蛋白胆固醇水平分别高于同龄野生型小鼠约7、2和30倍。随年龄增长apoE^-/-／LDLR^-/-小鼠主动脉内膜出现典型的动脉粥样硬化早期病变。结论上述脂代谢相关基因表达变化表明它们在动脉粥样硬化发生发展过程中起重要作用。

Expression profiles of lipid metabolism-related genes in liver of apoE(-/-)/LDLR(-/-) mice

OBJECTIVE: To explore the relationship between the expression characteristics of lipid metabolism-related genes in the liver and early atherosclerotic lesions in apolipoprotein E and low density lipoprotein receptor gene double knockout (apoE(-/-)/LDLR(-/-)) mice. METHODS: RT-PCR was used to detect the differential expression of lipid metabolism-related genes in the liver of apoE(-/-)/LDLR(-/-) and wild type (WT) mice. Serum total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) level as well as aortic morphology were also analyzed. RESULTS: Among the 11 lipid metabolism-related genes, apolipoprotein B100 (apoB100) mRNA levels were significantly higher in apoE(-/-)/LDLR(-/-)mice compared with WT mice. At 14 days, 1, 2 and 3 months of age, the level of mRNA expression were 1.55, 1.47, 1.50 and 2.42 folds of those of the age matched WT mice respectively. The fatty acid transporter (FAT/CD36) mRNA expression levels were higher in 14-day and 3-month old mice at 1.30 and 1.35 folds of those of the age matched WT mice, respectively. Apolipoprotein A IV (apoA IV) and Apolipoprotein AV (apoAV) mRNA levels were significantly down-regulated (0.89 fold decrease in 14-day, and 0.90 folds decrease in 3-month, respectively). The mRNA expression levels of apolipoprotein AI (apo AI), apolipoprotein F (apo F), peroxidase proliferator-activated receptor alpha (PPAR-alpha), liver X receptor alpha (LXRalpha), angiopoietin-like protein 3 (ANGPTL3), acyl-coenzymeA oxidase 1 (ACOX1) and carnitine palmitoyl transferase 1 (CPT1) had no significant changes. Serum TC, TG and LDL-C were higher than those of age matched WT mice at 7, 2 and 30 folds, respectively. Furthermore, apoE(-/-)/LDLR(-/-) mice demonstrated typical early atherosclerotic lesions at sinus and root regions of aorta in an age dependent manner. CONCLUSION: Alterations of the expression of lipid metabolism-related genes in liver play important roles in the development of AS in the apoE(-/-)/LDLR(-/-) mice at early ages.