中文摘要：

为了研究A族链球菌（GAS）作用巨噬细胞系RAW264.7后,RAW264.7细胞增殖变化的情况,以进一步研究GAS的致病机制。将RAW264.7接种于96孔板,采用低菌量、中菌量和高菌量分别作用于该细胞,培养三天后行MTT检测;用TUNEL及ANNEXIN V-FITC法检测高菌量GAS作用后巨噬细胞是否发生凋亡;透射电子显微镜观察低、中、高菌量GAS作用RAW264.7后细胞超微结构的变化。结果显示低、中菌量GAS对RAW264.7细胞增殖有促进作用;高菌量GAS对细胞增殖有抑制作用,且高菌量GAS作用RAW264.7后诱导大部分细胞发生了坏死而非凋亡。结果表明高菌量GAS引起RAW264.7细胞发生坏死而非凋亡。

英文摘要：

To study the proliferation of macrophage RAW264.7 infected with group A streptococcus （GAS）,exploring the pathogenic mechanism of GAS,RAW264.7 cells were seeded into 96 plates,and then infected with GAS at an MOI（multiply of infection） ranging from 5：1 to 100：1（bacteria number per macrophage） for 20 min, 40 min,60 min,90 min and 120 min,subsequently the bacteria were abandoned and the infected RAW264.7 cells were incubated for 3d,and then added MTT to measure OD_（490）.Following high-dose GAS stimulation,apoptosis was detected by TUNEL and ANNEXIN V-FITC.The ultrastructure of RAW264.7 cells,infected with GAS,was observed by transmission electron microscopy.We found that the activation and proliferation of RAW264.7 cells were enhanced following infections with low-dose GAS,while the proliferation of cells was declined when cells were infected with high-dose GAS,moreover,the cells were found to be necrosis but not apoptosis.Our results suggest that macrophages RAW264.7 are induced to be necrosis but not apoptosis with high-dose GAS simulation.