脂蛋白 (a)与巨噬细胞内脂质聚积关系的研究

目的：泡沫细胞形成是早期动脉粥样斑块的典型特征。本文通过对脂蛋白(a)[lipoprotein(a),Lp(a)]与巨噬细胞的相互作用进行研究,探讨Lp(a)与泡沫细胞形成的关系。方法：经生物素—亲和素—酶联法到定不同浓度生物素标记的天然及氧化型Lp(a)与小鼠腹腔巨噬细胞表面的结合量。天然及氧化型Lp(a)与小鼠腹腔巨噬细胞共同孵育后,酶法测定细胞内胆固醇及胆固醇酯含量的变化。结果：天然的Lp(a)能以一定的亲合力、可饱和的与巨噬细胞表面结合,氧化修饰后Lp(a)与巨噬细胞的结合量显著增加。天然及氧化型Lp(a)均能引起巨噬细胞的过量摄取,导致细胞内胆固醇含量增加,其中以氧化型Lp(a)的作用更为显著。与氧化型Lp(a)孵育后,巨噬细胞内胆固醇含量的增加是与天然Lp(a)孵育后的2．5倍,而胆固醇酯的含量增加是与天然Lp(a)孵育后的6．1倍。结论：Lp(a)能与巨噬细胞表面特异性结合,并促使细胞对其吞噬、降解;且巨噬细胞对氧化型Lp(a)的结合、摄取量显著增加。

Relationship between Lipoprotein(a) and the Cholestrol Accumulation in Macrophages

objectice:The large lesions of atherosclerosis characterized by the accumulation of foam cells.The interaction between macrophages with Lp(a)was studied to present how liporotein(a)plays roles in foam cell forming in the arterial wall.Methods:LP(a)binding assay with the mouse peritoneal macrophage were carried out by biotin avidin enzyme linked sorbent assay.The free and total cholesterol contents of the cells were determined after incubations with native Lp(a)or oxidizedLp(a)respectively by the enzymatic method.Results:Lp(a)was bound with affinity,saturation to macrophage surface.The value of Lp(a)binding with macrophages increased markedly after oxidative modification.The content of cholesterol in macrophages increased after incubating with LP(a)together whatever in native or oxidized Lp(a).oxidized Lp(a),however,induced higher rates of cholesterol accumulation,the values of content in cholesterol and its ester within macrophages increased 2.5-fold and6.1-fold than that in native Lp(a)respectively.Conclusions:Lp(a)can be bound to macrophages surface by special receptor,resulting enhanced uptake and degradation of Lp(a)by macrophages especially to the oxidized Lp(a).