【摘要】 为了研究高密度脂蛋白 3介导大鼠腹腔巨噬细胞内胆固醇流出的机理 ,用N -乙酰咪唑修饰高密度脂蛋白 3,阻断其与细胞表面受体的结合 ,观察细胞内胆固醇流出。用异硫氰酸荧光素酯标记高密度脂蛋白 3,示踪其在细胞内的代谢。结果发现牛血清白蛋白 (对照组 )介导 2 .87%细胞内胆固醇流出 ,高密度脂蛋白 3组和N -乙酰咪唑 -高密度脂蛋白 3组分别为 40 .6 8%和 8.6 9%。异硫氰酸荧光素酯 -高密度脂蛋白 3与细胞在 37℃共育 3h后 ,细胞内吞荧光强度占结合的 6 5 .0 % ,细胞在 37℃继续培养 2h后 ,细胞释放的荧光强度占内吞的 78.4% ,并且内吞和释放的荧光强度均主要存在于三氯醋酸沉淀部分。结果提示高密度脂蛋白 3通过与细胞表面受体作用进入细胞 ,在细胞内不经过溶酶体途径降解 ,而是接受细胞内胆固醇后通过逆胞饮形式释放到细胞外更多还原

【Abstract】 Aim To study the mechanism of cholesterol efflux from rat peritoneal macrophages mediated by high density lipoprotein-3(HDL 3). Methods Modification of HDL 3 by N-acetylimidazole blocked interaction between HDL and its cellular receptor. FITC labeled HDL 3 were used to observed the cellular metabolic process of HDL 3. Results BSA (control group) mediated 2.9% cellular cholesterol efflux from the cells. In HDL 3 group and N-acetylimidazole-HDL 3 group,they were 40.7% and 8.7% respectively. After incubation of macrophages with FITC-HDL 3 at 37℃for 3 h, the cell-endocytic fluorescence strength (FS) was 65.0% of the cell-associated FS. When the cells were further incubated with blank media at 37℃for 2 h, 78.4% of the cell-endocytic FS was released into the media. Both the cell-endocytic FS and the cell-released FS were mainly in trichloroacetic acid precepitable form. Conclusions The cellular cholesterol efflux from macrophages mediated by HDL 3 was HDL receptor-dependent. The possible mechanism could be that macrophages internalized HDL 3 by HDL receptor. HDL 3 picked up cellular cholesterol and was resecreted out of cells by a retroendocytic pathway without taking a celluar lysosomal phathway.更多还原