染料木黄酮的抗巨噬细胞泡沫化效应及其分子机制研究

目的 研究染料木黄酮对动脉粥样硬化过程中巨噬细胞泡沫化的抑制作用,并探讨其抗泡沫化的分子作用机制.方法 采用体外ox-LDL诱导小鼠单核巨噬细胞RAW264.7产生泡沫化,通过油红O染色观察细胞内脂质聚集程度判定细胞的泡沫化程度以及药物效应；利用报告基因细胞检测方法评价染料木黄酮对代谢性核受体过氧化物酶体增殖物激活受体PPAR和肝X受体LXR的转录调控功能的激动作用；利用实时定量PCR检测染料木黄酮对巨噬细胞中ox-LDL摄取以及胆固醇逆转运相关基因的mRNA水平.结果 ox-LDL处理的空白组小鼠RAW264.7单核巨噬细胞内聚积大量的脂质,而经过10 ug/ml染料木黄酮处理后的RAW264.7细胞内脂滴量明显减少,细胞泡沫化程度被大幅度降低.瞬时转染的细胞报告基因的转录激活效应研究结果说明,染料木黄酮对核受体PPAR和LXR均有较高的转录激活效应,其EC50值分别为3.5～9.2 μg/ml和1.6 ～ 3.3 μg/ml.定量PCR研究结果显示,染料木黄酮可以有效地使巨噬细胞中的胆固醇逆转运基因LXRα、LXRβ、ABCA1、ABCGl、和SR-B1的表达上调,而作为主要摄取ox-LDL受体的CD36基因的表达无明显变化.结论 染料木黄酮可以有效抑制动脉粥样硬化过程中巨噬细胞的泡沫化,而该作用机制可能是通过激活PPAR和LXR通路,上调胆固醇逆转运蛋白的ABCA1、ABCG1、LXRα、LXRβ、SR-B1基因的表达,增强了巨噬细胞的胆固醇外排,从而防止动脉粥样硬化的发生和发展.

Inhibitory effect of genistein on macrophage foam cell formation and its underlying molecular mechanisms

Objective To investigate the effects ofgenistein on macrophage foam cell formation and its underlying molecular mechanisms. Methods The foam cell was developed by treatment of RAW264.7 cells with 50μg/ml ox-LDL, and the lipid accumulation in cells was detected by oil-red O staining. The efficiency of genistein on the activities of peroxisome proliferators activated receptors （PPAR） and liver X receptor （LXR） were measured by reporter gene assays. The mRNA levels of genes in cells were analyzed by real time PCR. Results Compared with control, 10 pg/ml genistein resulted in a significant decrease in accumulation of lipid in RAW264.7 cells. In reporter gene assays, genistein could efficently induce the expression of luciferase modulated by PPAR and LXR with ECs0 values of 3.5 - 9.2 ~tg/ml and 1.6 - 3.3 pg/ml, respectively. Real time PCR results showed that genistein remarkably induced the expression of cholesterol efflux genes LXRct, LXR3, ABCA1, ABCG1 and SR-B1, and had no effect on macrophage ox-LDL receptor CD36. Conclusion Genistein can significantly inhibit the macrophage foam cell formation by activating the PPART-LXR-ABCA1 pathway of cholesterol effiux.