内毒素对人巨噬细胞系U937生物学性状和生长因子分泌能力的影响

Effect of lipopolysacharide on the biological features and growth factor secretion power of U937 cell line

目的 探讨不同浓度的内毒素 /脂多糖 (LPS)对人巨噬细胞系U937生物学性状和生长因子分泌能力的影响。 方法 分别以 0 .0、0 .1、1.0、10 .0、5 0 .0、10 0 .0 μg/ml的LPS刺激体外培养的U937,作用 2 4h后运用四氮噻唑蓝 (MTT)法测定细胞增殖活力 ,应用流式细胞仪测定细胞凋亡率 ,并用酶联免疫吸附测定法检测细胞培养上清中转化生长因子 β1(TGF β1)和血管内皮生长因子(VEGF)浓度的变化。 结果 与LPS为 0 .0 μg/ml时比较 ,当其浓度为 0 .1～ 10 0 .0 μg/ml时可刺激U937细胞凋亡、促进其分泌TGF β1(P <0.0 5～ 0.0 1),其中低浓度 (0 .1～ 10 .0 μg/ml)的LPS可促进U937增殖 (P <0.0 5～ 0.0 1),但对VEGF的分泌无明显影响 (P >0.0 5);高浓度 (5 0 .0、10 0 .0μg/ml)的LPS对U937的增殖无促进作用 (P >0.0 5 ),但能提高VEGF的分泌能力 (P <0.0 1)。结论 LPS可激活U937并促使其分泌TGF β1,刺激浓度以 0 .1～ 10 .0 μg/ml为宜 ;LPS仅在较高浓度时能促进U937细胞分泌VEGF。

Objective To investigate the effect of lipopolysacharide(LPS)in different concentrations on the biological features and growth factor secretion power of U937 cell line. Methods In vitro cultured U937 cells were stimulated by 0 (as control ),0.1,1.0, 10.0, 50.0 and 100 μg/ml LPS respectively for 24 hours. Thereafter, the cell proliferation ability was determined by MTT method. The cell apoptosis rate was determined by flow cytometry. The changes in the contents of transforming growth factor β 1(TGFβ 1) and vascular endothelial growth factor (VEGF) of the supernatant of the cell culture were assessed by ELISA. Results Apoptosis and TGFβ 1 secretion could be induced by LPS in dose of 0.1 to 100 μg/ml when compared with that without LPS challenge (P< 0.05-0.01). In detail, LPS in lower dose (0.1, 1.0 and 10.0 μg/ml) could promote the proliferation of U937 (P< 0.05-0.01) but exerted no effect on VEGF secretion. In contrary, LPS in high dose (50 and 100 μg/ml) could promote VEGF secretion (P<0.01) but exerted no effects on the proliferation of U937 cells. Conclusion U937 cells could be activated to increase the secretion of TGFβ 1 by LPS in optimal dose of 0.1-10.0 μg/ml, but the secretion of VEGF could only be promoted by LPS in higher concentration.