中文摘要：

目的探讨脂多糖（LPS）诱导小鼠巨噬细胞系RAW264．7细胞活化凋亡的作用。方法体外培养小鼠巨噬细胞系RAW264．7细胞，分别用0．5、1．0、2．5μg／ml LPS刺激RAW264．7细胞24h，一氧化氮（NO）试剂盒检测细胞培养上清中NO水平；用1．0μg／ml LPS分别刺激细胞3d和6d，台盼蓝拒染法检测细胞增殖情况；用1．01μg／ml LPS刺激细胞6d，流式细胞术分析细胞周期及细胞凋亡情况。结果经LPS刺激后24h，RAW264．7细胞培养上清中NO含量明显增加，且具有剂量依赖性；LPS刺激3d和6d后，细胞的增殖均受到抑制，且呈时间依赖性；LPS刺激6d时，细胞周期被阻滞在S期，并出现明显的凋亡。结论LPS具有诱导小鼠巨噬细胞系RAW264．7细胞活化凋广的作用。

英文摘要：

Objective To explore the role of lipopolysaccharide （LPS） in activation-induced apoptosis of mouse macrophage RAW264. 7. Methods RAW264. 7 ceils were cultured in vitro and stimulated with LPS at dosages of 0. 5, 1. 0 and 2. 5 μg/ml for 24 h respectively and determined for nitric monooxide（NO） level in culture supernatant by NO kit. The cells were stimulated with 1. 0 μg/ml LPS for 3 and 6 d respectively and determined for proliferation level by trypan blue dye exclusion method. The cells were also stimulated with 1.0μg/ml LPS for 6 d and analyzed for cell cycle and apoptosis by flow cytometry. Results After stimulation with LPS for 24 h, the NO level in culture supernatant of RAW264. 7 cells showed a dose-dependent increase. After stimulation with LPS for 3 and 6 d, the proliferation of RAW264. 7 cells was inhibited in a time-dependent mode. After stimulation with LPS for 6 d, the cell cycle was blocked at S phase, and obvious apoptosis was observed. Conclusion LPS plays an important role in activation-induced apoptosis of mouse macrophage RAW264. 7.