中文摘要：

目的体外观察葡萄球菌肠毒素A（SEA）对人肝癌细胞株SSMC7721的增殖抑制作用，旨在为肝癌的治疗提供理论依据。方法应用噻唑蓝（MTT）比色法检测不同浓度（0、20、40、80μg／L）的SEA对SSMC7721细胞的增殖抑制率，流式细胞仪检测细胞周期进程的变化，荧光显微镜检测细胞凋亡情况。结果0、20、40、80μg／L浓度的SEA吸光度（A）值分别为1．52±0．12，1．14±0．13，0．98±0．16，0．82±0．21；根据吸光度值计算SSMC7721细胞增殖抑制率分别为0、（18．4±1．3）％、（35．5±0．9）％、（46．7±1．6）％，多组间经统计学处理，差异有统计学意义（F=4．63，P〈0．05），其他3组与0μg／L组比较，差异均有统计学意义（P均〈0．01）；显示不同浓度的SEA对SSMC7721细胞增殖均有抑制作用，且呈剂量依赖性。流式细胞仪检测结果显示：不同浓度的SEA对SSMC7721细胞均有影响，G0／G1期细胞增多，S期细胞减少，G2／M期细胞相对增多；荧光染色结果显示正常SSMC7721细胞凋亡率为1．0％，而20、40、80μg／L浓度的SEA对SSMC7721细胞凋亡率分别为12．5％、19．4％和23．2％。结论SEA能显著抑制SSMC7721细胞增殖，抑制SSMC7721细胞G1期向S期转化进程，诱导SSMC7721细胞凋亡。

英文摘要：

Objective We detected the proliferation inhibition effect of staphylococcal enterotoxin A （SEA） on human liver cancer SSMC7721 cell lines in vitro to provide a theoretical basis for the therapy of liver cancer. Methods We applied MTY colorimetric method to assay the SSMC7721 cell＇s proliferation inhibition rate treated by different concentrations （ 0 p.g/L, 20 μg/L, 40 p.g/L and 80 μg/L） of SEA. We decided the changes of the cell cycle progression by flow cytometry and the apoptosis rate by fluorescence microscopy. Results When the SSMC7721 cells were treated with different concentrations（20 μg/L,40 μg/L and 80 μg/L） of SEA, cell proliferation inhibition rates were （ 18.4± 1.3 ） % , （ 35.5± 0. 9 ） % , （ 46. 7±1.6） % respectively and the statistical differences were significant compared to the control group （P 〈 0. 01 ）, and the proliferation is in an obvious dose dependent manner. Flow eytometry results indicated that the cells in the GO/G1 period increased;the cells in the S period decreased;the cells in the G2/M period increased. Cell apoptosis rates after treatment by 20 μg/L,40 μg/L and 80 μg/L SEA increased to 12. 5% , 19.4% and 23.2% respectively from 1.0% without SEA treatment. Conclusion SEA can significantly increase the cells proliferation inhibition rate and inhibit the cell＇s transformation from G1 to S period in SSMC7721 cell and induce the SSMC7721 cellμ apoptosis.