目的 观察知母皂苷AⅢ对体外培养黑色素瘤B16细胞增殖和凋亡的影响。方法 体外培养B16细胞，分别以浓度为1，2，4，8，16 μmol•L-1的知母皂苷AⅢ作用24 h，通过MTT比色法检测对细胞生长的影响；倒置显微镜观察对细胞形态的影响；Annexin V-FITC/PI双染流式检测对细胞凋亡的影响；逆转录PCR检测对细胞凋亡相关基因Bax，Bcl-2的影响。结果 8，16 μmol•L-1的知母皂苷AⅢ明显抑制细胞增殖，24 h的半数抑制浓度（IC50）为10.16 μmol•L-1；细胞形态显示16 μmol•L-1的知母皂苷AⅢ使细胞体积缩小变圆，细胞减少。与对照组比较，10 μmol•L-1知母皂苷AⅢ细胞凋亡率为（4.83±0.25） %（P＜0.01），而Bax/Bcl-2比值升高（P＜0.05）。结论 体外实验显示知母皂苷AⅢ能明显抑制B16细胞生长，并能诱导部分细胞发生凋亡。由于诱导细胞凋亡率与24 h的IC50有一定差距，因此知母皂苷AⅢ对B16细胞生长的影响可能不仅仅与激活凋亡信号通路有关，还与其他细胞生长信号通路有关。

Objective To observe the effect of timosaponin AⅢ on the proliferation and apoptosis of cultured melanoma B16 cells in vitro．Methods B16 cells were cultured in vitro together with timosaponin AⅢ at the concentrations of 1，2，4，8，16 μmol•L-1 respectively for 24 h. MTT assay was adopted to detect the cell growth inhibition．The morphological changes of melanoma B16 cells were observed under inverted microscope. The apoptosis of melanoma B16 cells were detected by flow cytometry after stained with Annexin V-FITC/P. The mRNA expression levels of Bcl-2 and Bax were detected by reverse transcription PCR. Results Timosaponin AⅢ（8，16 μmol•L-1） significantly inhibited the proliferation of B16 cells，and the IC50 was 10.16 μmol•L-1 after treatment for 24h. The cell density got less，and the cell shape got small and round after treatment with 16 μmol•L-1 of timosaponin AⅢ. The apoptotic rate of melanoma B16 cells was（4.83±0.25） % after treatment with 10 μmol•L-1 of timosaponin AⅢ（P＜0.01）. Timosaponin AⅢ（10 μmol•L-1） significantly increased the mRNA expression levels of Bax/Bcl-2 in melanoma B16 cells. Conclusion Timosaponin AⅢ could inhibit the proliferation and induce the apoptosis of melanoma B16 cells in vitro．The apoptotic rate and 24-hour IC50 were not in the same pace， indicating that the therapeutic mechanism of timosaponin AⅢ on the growth of B16 cells may be not only related to the activation of apoptosis signal pathway，but also be relevant to other cell growth signaling pathway.

R285.5

上海市皮肤病医院青年人才培养计划（No.2013）。