EXPERIMENTAL MODEL OF GASTRIC CARCINOGENESIS WITH N-METHYL-N-NITROSOUREA FOR F344 RATS AND C3H MICES IS VALID FOR WISTAR RATS?

摘要

Background: The N-methyl-N-nitrosourea (MNU) is a direct acting carcinogen, inducing tumors in several species in a variety of organs, including stomach of rats. Treatment of MNU in the drinking water for 25-42 weeks selectively induced glandular gastric carcinoma in F344 rats and C3H mice. Aim: To establish an experimental model for selective MNU induction of glandular stomach cancer in Wistar rats. Methods: A total of 48 males eight-week-old Wistar rats were used in the present study. MNU (Sigma-Aldrich) was dissolved in DMSO and provided as the drinking water ad libitum for a period ranging from 16 to 70 weeks. After 16 weeks, four rats were randomly selected and killed. After every six weeks four animals were killed until 70 weeks. Results: Survival rate was higher than 90. It had the induction of two adenocarcinomas, one squamous cell carcinoma and one sarcoma. The incidence of gastric adenocarcinoma was 4.5 (0.5 to 15). Conclusions: The experimental model of gastric carcinogenesis in Wistar rats, using MNU dissolved in water, showed not practice viability in this study due to the low rate of gastric adenocarcinoma.