Comparison Of Two Kinds Of Ectopic Implantation Of Colon Cancer Liver Metastasis Animal Models

Objective:Colorectal cancer is one of the most common malignant tumors. The main factor affecting the prognosis of patients with colorectal cancer was tumor recurrence or metastasis, and liver is the main transfer target organ of colorectal cancer by blood. In this study, we compared liver metastasis rate and its effects in two groups, hepatoportal injection group and spleen injection with spleen excision group.Methods:Sixty BALB/c mice, half male and half female, were randomly divided into hepatoportal injection group and spleen injection with spleen excision group, with injecting0.2ml mice colon adenocarcinoma (CT26) cell suspension with concentration of1x106/ml. We compared the two animal groups of liver metastasis rate and tumorigenic effects, and survival time of mice when mice died of natural causes. SPSS13.0statistical software was used to analyze data. Liver metastatic tissues were used for pathological examination.Results:(1) General observation was similar in the two groups. BALB/c mice have normal activities within postoperative10d. Mice began to appear food intake dropped, thin, abdomen gradually distention after postoperative10d, but no mice died. Mice were badly after postoperative20d, and the first mouse died of natural causes in hepatoportal injection group when postoperative22d. Most mice died during postoperative30d to55d, and the last one died in spleen injection with spleen excision group after postoperative58d.(2) There are30mice in each group with establishing successful animal modes. The liver metastases rate was96.7%in hepatoportal injection group and80%in spleen injection with spleen excision group (P=0.044).(3) Tumorigenicity of liver metastases:liver metastases of tumor were described as a highly metastatic degree:metastatic lesions covered the whole liver; moderately metastatic degree: metastases accounted for1/2of the liver and above; lowly metastasis degree: metastases accounted for less than1/2of the liver. Hepatoportal injection group have more cases of mice in highly and moderately metastatic degree than spleen injection with spleen excision group.(4) Survival time was during postoperative22-55d, with a mean of (34.6±8.7) d in hepatoportal injection group, and postoperative30～58d, with a mean of (49.3±7.8) d in spleen injection with spleen excision group. There are significant difference in these two groups (P=0.000).(5) Microscopically, the liver metastases of cancer cells were in line with the structural features of poorly differentiated adenocarcinoma with gathering into a group, nodules, irregular cancer cell shape, poorly differentiated, shaped significantly less cytoplasmic, and deeply stained, mitosis.Conclusion:This study compared the two colon cancer liver metastasis mice model. Hepatoportal injection group have higher liver metastasis rate and tumorigenicity of liver metastases and was more suitable for experimental research requiring higher liver metastasis rate. Spleen injection with spleen excision group has longer survival time and was more suitable for research requiring longer period of drug study.