论文部分内容阅读
为研究载脂蛋白Ｅ含量不同的极低密度脂蛋白对巨噬细胞载脂蛋白Ｅ表达的影响，以肝素－琼脂糖凝胶亲和层析法将正常人极低密度脂蛋白分离为富含载脂蛋白Ｅ和贫含载脂蛋白Ｅ的二种不同亚组分，并分别以不同浓度与小鼠腹腔巨噬细胞共培养。而后以Ｎｏｒｔｈｅｒｎ印迹分析和十二烷基硫酸钠－聚丙烯酰胺凝胶电泳的方法研究了其对小鼠腹腔巨噬细胞载脂蛋白Ｅ基因表达的不同影响。结果发现，两种极低密度脂蛋白亚组分在较低浓度（含甘油三酯１００μｇ／Ｌ）时均可刺激小鼠腹腔巨噬细胞载脂蛋白Ｅ基因的表达，且尤以贫含载脂蛋白Ｅ的极低密度脂蛋白作用更为明显，其刺激后的细胞ｍＲＮＡ及蛋白质表达分别增高约１．５８和１．８２倍。但高浓度的二种极低密度脂蛋白亚组分刺激的细胞ｍＲＮＡ水平下降为对照的６５％，而蛋白质水平却升高２倍之多，其机制未明。上述实验结果说明，贫含载脂蛋白Ｅ极低密度脂蛋白可能在较低浓度下具有更强的刺激小鼠腹腔巨噬细胞载脂蛋白Ｅ基因表达的能力，而高浓度时则不然。
In order to study the effect of very low density lipoproteins with different contents of apolipoprotein E on the expression of apolipoprotein E in macrophages, normal human very-low-density lipoprotein was separated by heparin-sepharose affinity chromatography Apolipoprotein E and apolipoprotein E-deficient sub-fractions were co-cultured with mouse peritoneal macrophages at various concentrations. Then, different effects on apolipoprotein E gene expression in mouse peritoneal macrophages were studied by Northern blot analysis and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The results showed that both of the very low density lipoprotein sub-components could stimulate the expression of apolipoprotein E gene in mouse peritoneal macrophages at lower concentration (including triglyceride 100μg / L) The effect of LDL of lipoprotein E was more obvious. The mRNA and protein expressions of stimulated cells were increased by about 1.58 and 1.82 times, respectively. However, the mRNA levels of the cells stimulated by the two high-density, very-low-density lipoprotein subfractions decreased to 65% of the control, whereas the protein level increased by two-fold. The mechanism was unclear. The above experimental results show that poor apolipoprotein E very low density lipoprotein may have stronger ability of stimulating the expression of apolipoprotein E gene in mouse peritoneal macrophages at lower concentration, but not at high concentration.