【摘要】 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。更多还原

【Abstract】 Aim To study the differential effects of human very low density lipoprotein (VLDL) subfractions with different apolipoprotein E content on the expression of apolipoprotein E gene in mouse peritoneal macrophages (MPMs). Methods Apolipoprotein E-rich and apolipoprotein E -poor subfractions of normal human VLDL with different apolipoprotein E content were separated by Heparin-sepharose CL-6B affinity chromatography and incubated with MPMs at different concentrations respectively. Their effects on the expression of MPM apolipoprotein E gene were determined at both mRNA and protein level with Northern blotting essay and SDS-polyacrylamide gel electrophoresis respectively. Results At concentration of triglyceride 100 μg /L medium, both apolipoprotein E-rich and apolipoprotein E-poor subfractions could stimulate expression and secretion of apolipoprotein E in MPMs, with apolipoprotein E-poor subfraction demonstrating more potent:a nearly two-fold increase in the mRNA and protein level (1.58 and 1.82-fold respectively) was observed in the cells treated with apolipoprotein E-poor subfraction compared to the slight increase in cells treated with its apolipoprotein E-rich counterpart (1.10 and 1.25-fold respectively). However, the case was quite different for cells treated with that two subfractions at 1 000 μg/L of triglyceride medium. The mRNA level was similarly inhibited to a level of 65% of control cells in contrast to elevated apolipoprotein E protein level at more than two-fold. However, the reasons remain obscure at present. Conclusion These findings might suggest that apolipoprotein E -poor VLDL has higher potentiality to stimulate the expression of apolipoprotein E at only relatively low concentration, but does not at high concentration level.更多还原