低密度脂蛋白免疫复合物对小鼠腹腔巨噬细胞胆固醇酯蓄积和一氧化氮释放的影响

目的 探讨低密度脂蛋白免疫复合物对小鼠腹腔巨噬细胞胆固醇酯的蓄积和一氧化氮释放的影响。方法 密度梯度超速离心从新鲜人血浆分离天然低密度脂蛋白，与抗低密度脂蛋白抗血清IgG组分制备低密度脂蛋白免疫复合物，低密度脂蛋白免疫复合物与小鼠腹腔巨噬细胞孵育后采用酶荧光法检测细胞胆固醇酯含量，进行细胞形态学观察和组织化学分析．并用硝酸还原酶法测定细胞释放至培养基中的一氧化氮量。结果 低密度脂蛋白免疫复合物剂量依赖性地诱导巨噬细胞内胆固醇酯的大量堆积，其效应显著强于氧化型低密度脂蛋白（P〈0．01）。经低密度脂蛋白免疫复合物处理的巨噬细胞呈典型泡沫细胞状，与猩红强染色，而天然低密度脂蛋白、抗低密度脂蛋白IgG处理的巨噬细胞内未见胆固醇酯的蓄积。此外，低密度脂蛋白免疫复合物剂量依赖性地抑制巨噬细胞一氧化氮的分泌。结论 低密度脂蛋白免疫复合物不仅通过致小鼠腹腔巨噬细胞泡沫化，也通过损伤巨噬细胞分泌一氧化氮的功能参与致动脉粥样硬化作用。

The Effects of Low Density Lipoprotein Immune Complexes on the Accumulationof Cholesteryl Ester in Mouse Peritoneal Macrophages and on the Release of Nitric Oxide from the Macrophages

Aim To investigate the effects of low density lipoprotein immune complexes (LDL-IC) on the accumulation of cholesteryl ester (CE) in mouse peritoneal macrophages and on the secretion of nitric oxide (NO) from the macrophages. Methods LDL was isolated from fresh human plasma by ultracentrifugation, and then LDL-IC was prepared by incubating LDL with IgG fraction of a sheep anti-LDL antiserum in vitro. After mouse peritoneal macrophages were incubated with LDL-IC, cellular cholesteryl ester mass was quantified by an enzymatic fluorometric methods and the morphological observation and histochemistry of macrophages were performed. In addition, nitric oxide secreted from macrophages to the medium was measured by nitric acid reductase method. Results The levels of cellular CE in macrophages were increased markedly with LDL-IC dose dependent manner, which was significantly higher than that induced by corresponding level of oxidized LDL(ox-LDL)(P<0.01). Whereas native LDL and apoB-IgG did not show any effect on the level of cellular CE. Morphologically, after exposure to LDL-IC, macrophages exhibited a phenotype typical of lipid-laden foam cell, becoming strongly stained with scarlet. In addition, the content of NO in the medium released from the macrophages were decreased and also showed a LDL-IC dose dependent manner. Conclusion LDL-IC participates in atherosclerotic formation not only by inducing the formation of foam cell, but also by damaging the function of NO of macrophages.