A new experimental model for colorectal carcinogenesis in the rat.

A total of 130 rats were used in various experiments to prepare a new model for colorectal carcinogenesis. The experiments resulted in the development of a surgical technique that creates a subcutaneous cecal hernia, which allows the direct injection of the promoting substance, human bile from percutaneous biliary drainage, into the bowel of the rat. The method permits a direct, complete, and very easy access of a specific amount of the substance to be tested onto the colonic mucosa. The results have proven to be uniformly effective and easily reproducible and to ensure safe management of the animal.