氧化高密度脂蛋白对单核细胞膜脂流动性及淋巴细胞功能相关抗原-1表达的影响

Effects of oxidized high-density lipoprotein on membrane fluidity and the expression of lymphocyte function associated antigen-1 of monocyte

目的 :研究氧化高密度脂蛋白 (oxHDL)对单核细胞膜脂流动性及淋巴细胞功能相关抗原 - 1(LFA - 1)表达的影响。方法 :采用荧光探针DPH检测膜脂流动性 ,用流式细胞术间接免疫荧光法检测人单核细胞株THP - 1细胞表面LFA - 1的表达水平。结果 :10 0 μgprotein/mL的oxHDL和oxLDL(氧化低密度脂蛋白 )作用 2 0h后可显著降低THP - 1细胞膜脂流动性 (LFU) ,分别较对照组低 45 %和 5 2 % (P <0 .0 1) ;oxHDL作用 2 4h可明显促进LFA - 1的表达 ,阳性细胞率和平均荧光强度分别较对照组高 39%和 45 % (P <0 .0 1)。结论 :ox HDL可能通过促进单核细胞表达LFA - 1而使更多的单核细胞粘附于内皮 ,它还可降低单核细胞膜脂流动性 ,这将使单核细胞在进入内皮下层后难于重新返回循环血中 。

AIM: To investigate the effects of oxidized high-density lipoprotein (oxHDL) on membrane fluidity and the expression of lymphocyte function associated antigen(LFA-1) of monocyte. METHODS: The membrane fluidity of THP-1 cells was assayed by fluorescence anisotropy with DPH (1,6-dipheny-1,3,5-hexatriene), a fluorescent probe; The LFA-1 expression on THP-1 cells were assayed by flow cytometry with indirect immunofluorescence.RESULTS: The membrane fluidity of THP-1 cells was reduced by 45% and 52% respectively ( P <0.01) after incubation with 100 μg protein/mL oxHDL and oxLDL for 20 h; oxHDL could stimulated the expression of LFA-1 on THP-1 cells, the positive cell rate and mean fluoresence intensity (MFI) increased by 39% and 45% respectively versus control group ( P <0.01) after incubation with cells for 24 h. CONCLUSIONS: By increasing the expression of LFA-1 on monocyte, oxHDL can promote the monocyte-endothelium adhesion; oxHDL also can reduce the membrane fluidity of monocyte, that will limit the returning of monocytes from subendothelium back to the circulation. This suggested that oxHDL may play an important role in atherogenesis.