目的:探讨蟾毒灵治疗裸鼠结肠癌原位移植瘤的作用及机制。方法 :应用不同剂量蟾毒灵(0.5、1.0、1.5 mg/kg)处理人结肠癌细胞株HCT-116建立的裸鼠原位移植瘤模型,分别用生理盐水(NS)(0.2 mL/只)、5-FU(25 mg/kg)做阴性(NS组)和阳性对照(5-FU组),测量移植瘤的体积,观察蟾毒灵对移植瘤的肿瘤抑制率、裸鼠生存期的影响;HE染色观察移植瘤的坏死程度;TUNEL标记法检测肿瘤细胞的凋亡指数;荧光定量PCR方法检测基因Caspase-3 mRNA的表达,免疫组化法和Western印迹法检测Caspase-3蛋白的表达。结果:蟾毒灵各剂量组和5-FU组裸鼠原位移植瘤体积明显小于NS组(P<0.05);NS组,5-FU组和蟾毒灵0.5、1.0、1.5 mg/kg剂量组的裸鼠中位生存期分别为40、37和47、46、45 d,生存分析显示蟾毒灵各剂量组裸鼠的生存时间与NS组相比明显延长;1.0和1.5 mg/kg剂量组和5-FU组移植瘤的坏死程度增加(P<0.05);蟾毒灵各组移植瘤的凋亡指数与NS组相比明显增加(P<0.05),凋亡相关基因Caspase-3 mRNA和蛋白表达明显升高(P<0.05)。结论:蟾毒灵能够抑制裸鼠人结肠癌原位移植瘤的生长,促进肿瘤细胞凋亡,其机制可能与上调基因Caspase-3表达有关。 Objective: To investigate the effect and mechanism of bufalin on orthotopic colon carcinoma in nude mice. Methods: Nude mice xenografted model of human colon cancer cell line HCT-116 were treated with different doses of bufalin (0.5, 1.0 and 1.5 mg / kg), respectively. NS (0.2 mL / body) , 5-FU (25 mg / kg) as negative group (NS group) and positive control group (5-FU group). The volume of xenografted tumor was measured and the effect of bufalin on the tumor growth inhibition rate and the survival of nude mice The necrosis degree of tumor was observed by HE staining. The apoptosis index of tumor cells was detected by TUNEL method. The expression of Caspase-3 mRNA was detected by real-time PCR. The expression of Caspase-3 protein was detected by immunohistochemistry and Western blotting. Results: The in situ xenograft tumor volume in each group of bufalin and 5-FU group was significantly smaller than that in NS group (P <0.05). The NS, 5-FU and bufalin doses of 0.5, 1.0 and 1.5 mg / kg The median survival time was 40, 37 and 47, 46 and 45 days in nude mice, respectively. Survival analysis showed that the survival time of nude mice in each dose of bufalin significantly prolonged compared with that in NS group. The dose of 1.0 and 1.5 mg / kg (P <0.05). The apoptosis index of allograft groups of bufalin group was significantly higher than that of NS group (P <0.05), while the apoptosis related gene Caspase-3 mRNA And protein expression was significantly increased (P <0.05). Conclusion Bufalin can inhibit the growth of xenografted human colon carcinoma xenografts in nude mice and promote the apoptosis of tumor cells. The mechanism may be related to the upregulation of Caspase-3 expression.