Role of VEGF in establishment of Walker-256 transplanted liver cancer model in SD rats

AIM：To evaluate the safety and feasibility of using vascular endothelial growth factor (VEGF) in the establishment of Walker-256 transplanted liver cancer model. METHODS：SD rats (n=45) were divided into 3 groups:via the caudal vein, the rats in normal saline (NS) group were injected with 0.9% sodium chloride (0.1 mL/d), the rats in 20 mg/L VEGF group were injected with 20 mg/L VEGF (0.1 mL/d), and the rats in 40 mg/L VEGF group were injected with 40 mg/L VEGF (0.1 mL/d). All the injection began 1 week before transplantation of liver cancer, and stopped on the day the cancer model was established. Prepared tumor tissue was transplanted into the subcapsular space of the liver. Three days, 1 week and 2 weeks after the transplantation, magnetic resonance imaging (MRI) was performed for analyzing the tumor growth and the characteristics. The overall survival of the rats was also recorded. RESULTS：Successful establishment of Walker-256 transplanted liver cancer model was achieved. Among 45 rats, 1 rat died 1 d after implanting the tumor both in NS group and 20 mg/L VEGF group, while 3 rats died in 40 mg/L VEGF group 1 week after building the model, mainly because of the progression of tumors. Three days after modeling,the numbers of the rats in which the tumor was positively detected by MRI in 3 groups were 0, 7 and 10, respectively; 1 week after modeling, those were 3, 13 and 13, respectively; 2 weeks after modeling,those were 12, 13 and 10， respectively. Between NS group and 20 mg/L VEGF group, the statistical significance existed in the number of the rats in which the tumor was positively detected by MRI after 3 d of implanting, so did the NS group and 40 mg/L VEGF group. No statistical significance in the overall survival time between NS group and 20 mg/L VEGF group (P＞0.05) was observed, but the significance existed between 40 mg/L VEGF group and NS group (P<0.01). CfONCLUSION:The application of VEGF at dose of 20 mg/L and 0.1 mL/d shortens the time to establish the transplanted liver cancer model without influence on the overall survival, which is a safe, feasible and efficient way, and is more suitable for anti-VEGF drug investigation.