A Novel Modified Model for Induction of Intestinal Adenomas in Female Mice

Background An azoxymethane/dextran sulfate sodium (AOM/DSS) protocol has been developed for the induction in an animal model of the precancerous stages of colitis-associated carcinogenesis, by modification of the established (AOM/DSS protocol for carcinogenesis. Methods Female C57BL6 mice were treated with a single intraperitoneal dose (10 mg/kg of body weight) of AOM followed by three, 5-day, cycles of oral DSS, at different dosages, with each cycle interrupted by a 2-week rest period. Results The 3 mice in the group that were given three, 5-day, cycles of oral 2.5 % DSS all developed colonic adenomas with dysplastic lesions, but none had developed adenocarcinoma at 60 days. In contrast, of 6 mice treated with AOM administration along with either three, 5-day, cycles of 3.0% DSS or three, 7-day, cycles of 2.5% DSS, 5 had developed cancer at day 84 of the experiment. These results suggest that the administration of three, 5-day, cycles of 2.5% DSS following an initial dose of AOM may successfully induce adenoma formation in female C57BL6 mice at day 60, without the concurrent presence of carcinoma. Conclusion This modification of the widely used AOM/DSS protocol for induction of colonic carcinoma may constitute a novel approach for investigating colitis-related colonic adenomas.