The Establishment And Research Of Transplantation Model Of Human Colon Cancer In Nude Mice

Objective:To establish subcutaneous injection model,intrasplenic injection model and orthotopic transplantation model of human colon cancer respectively,study the characteristic of their biological behaviour,provide available animal models for the research of human colon cancer.Methods: Exponentially growing HCT-116 cells were inoculated subcutaneously onto flank or injected into spleen of separate BALB/c nude male mice in order to establish subcutaneous implantation model and intrasplenic injection model. Once the subcutaneous xenografts were established, they were excised and minced into small pieces, one of the pieces was then orthotopically implanted into the cecum of other male BALB/c nude mice. Observe and analyze the rate of tumor formation,tumor growth,metastasis and ascites formation of each group model.Results:(1) Tumor growth could be seen in every mouse in the group of the subcutaneous implantation model. One week after the operation, visible mass was about 0.3cm in diameter. During 4 weeks, we did not see local invasion, lymphatic metastasis or distant metastasis.(2) In the group of intrasplenic injection model, the animals were euthanized after 6 weeks of tumor cells injection when they were thin obviously, arched their back and acted dilatorily. The cell line gave rise to a primary tumor in spleen in 100% of the animal(6/6), the rate of liver metastasis was 66.7%(4/6). At the same time, some mice appeared serious abdominal cavity metastasis and ascites formation.(3) In the group of orthotopical implantation model, animal cachexia appeared 12 weeks later after the operation when they were euthanized. The implanted mice generated cecum tumor in 80% animals and gave riseto metastasis to liver in 40% animals. Abdominal cavity metastasis and ascites formation were not been seen.Conclusions:(1) The subcutaneous injection model, with a high rate of tumor growth, is easy to operate. The measurement and observation of the tumor can be done easily. It can be used as a good model for research of solid tumor growth, rather than local invasion and distant metastasis.(2) The rate of live metastasis is high in the group of intrasplenic injection model. It provides available model for the study of metastasis of colon cancer. However, it can only simulate the last stage of the whole process of tumor metastasis.(3) The operation of orthotopic transplantation tumor model is relatively complicated. The time of metastasis to live from the primary tumor is longer than intrasplenic injection model. Many factors may influence the results during the process of operation. But the advantage is that it can imitate the biological behavior of human colon cancer in vivo, including the whole process of tumor metastasis. So it can be seen as the ideal animal model of colon cancer.