Objective To invest the inhibitory effect of tumor growth and the expression of vascular endothelial growth factor (VEGF) by acetoacetate extractive of Celastrus orbiculatus Thunb in orthotropic human liver carcinoma nude mice model. Methods Human HCC HepG2 cells transduced with red lfuorescent protein (RFP-HepG2) were inoculated into the liver of BALB/c nude mice. The tumor-bearing nude mice were randomly divided into ifve groups:control group (G1 group), Oxaliplatin positive control group (G2 group, 25 mg/kg), COT low dose group (G3 group, 20 mg/kg), COT high dose group (G4 group, 40 mg/kg) and COT early treatment group (G5 group, 20 mg/kg). G5 group of mice was treated with COT p.o. from day 2 post tumor implantation. All other mice were treated from day 20 post tumor implantation. The growth of xenografted tumors was traced weekly by in vivo lfuorescence imaging technology. Real time whole body lfuorescence imaging was performed to measure tumor growth during the study. At the end of treatment, all of mice were killed and tumor tissue were collected. VEGF expression in the tumors collected at autopsy was analyzed by immunohistochemical staining. VEGF mRNA expression in the tumors collected at autopsy was analyzed by reverse transcription-polymerase chain reaction (RT-PCR). Results The COT signiifcantly inhibited the growth of xenografted tumors. The inhibitory effect of COT in G5 group was superior to those in G3 group and G4 group, which was almost close to G2 group. VEGF protein was found to be expressed in the cytoplasm of all liver cells and the cell membrane of some liver cells. Average optical density (D) of the tumor VEGF expression was signiifcantly reduced by high-dose COT and early COT treatment, compared to G1 group and G3 group (t=4.657, 6.440, 7.712, 8.900;P=0.0037, 0.0031,<0.001,<0.001). The tumors from early treatment with COT and oxaliplatin-treated mice had signiifcantly lower VEGF expression levels compared to all other COT-treated mice. Consistent with VEGF protein expression by immunohistochemistry, the tumor VEGF mRNA expression was signiifcantly reduced by G4 group and G5 group, compared to G1 group and G3 group (t=6.320, 7.563, 12.907, 12.545;P=0.0002, 0.0003,<0.001,<0.001). Conclusions The acetoacetate extractive of C. articulatus Thunb possess the effect of anti-tumor in vivo. The COT inhibits the growth of tumor. Inhibit VEGF expression by COT may inhibit angionesis and then may contribute in part to the inhibition of tumor growth.%目的：建立裸鼠原位人荧光蛋白肝癌移植瘤模型，研究不同处理组肿瘤组织VEGF的表达变化，探讨南蛇藤乙酸乙酯提取物对人肝癌生长抑制作用的相关机制。方法BALB/c裸鼠肝脏接种荧光蛋白标记的人肝癌细胞（RFP-HepG2），建立肝癌动物模型并随机分为空白对照组（G1组）、奥沙利铂阳性对照组（G2组，25 mg/kg）、南蛇藤小剂量治疗组（G3组，20 mg/kg）、南蛇藤大剂量治疗组（G4组，40 mg/kg）和南蛇藤预防治疗组（G5组，20 mg/kg）。奥沙利铂为尾静脉注射给药，南蛇藤为灌胃给药，G1组用等渗盐水替代，G3组、G4组自RFP-HepG2细胞接种第20天开始每日给药1次，连续4周。G5组自RFP-HepG2细胞接种第2天开始给药至治疗结束。治疗结束后组织标本进行VEGF免疫组织化学染色，采用Image-pro plus 6.0（IPP）软件分析，用平均光密度评估各图片免疫组织化学染色程度。采用RT-PCR方法检测标本VEGF表达。结果南蛇藤可抑制体内、外肿瘤细胞的生长， G4组、G5组对肿瘤的抑制更明显，与之结果相一致，G2组的VEGF阳性表达率最低，G4组、G5组的VEGF阳性表达率显著低于G3组与G1组（t=4.657、6.440、7.712、8.900，P=0.0037、0.0031、＜0.001、＜0.001）。各实验组肿瘤组织VEGF mRNA水平与免疫组织化学显示VEGF表达呈平行关系。奥沙利铂治疗组的VEGF mRNA水平最低，G4组、G5组的VEGF mRNA水平显著低于G1组、G3组（t=6.320、7.563、12.907、12.545，P=0.0002、0.0003、＜0.001、＜0.001）。结论南蛇藤乙酸乙酯提取物可抑制裸鼠原位人荧光蛋白肝癌移植瘤模型肿瘤的生长及人肝癌细胞中VEGF表达，提示南蛇藤可能通过抑制人肝癌细胞中VEGF的表达来抗肝癌血管形成，从而抑制肝癌细胞的生长和转移。
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