THE EFFECT OF ASPIRIN ON THE DIMETHYLHYDRAZINE -INDUCED COLONIC CARCINOMA.

Abstract

86 Recent studies have revealed that aspirin and other NSAIDs regular intake can decrease colorectal polyp formation and have a strong epidemiological link to colorectal cancer prevention. Dimethylhydrazine-rat model may represent the unstable colonic epithelium in familial polyposis and inflamatory bowel disease. The aim of this study is to assess the role of aspirin on the dimethylhydrazine-induced colorectal cancer in rats. The study population consisted of 45 seven week old female wistar rats. Colorectal tumours were induced with 20 weekly subcutaneous injections of 1,2-dimethylhydrazine[20mg/kg BW]. They were fed commercial diet containing 3% crude fiber. The rats were randomly divided into three groups. Group A: 15 rats receiving only the carcinogen. Group B: 15 rats receiving the carcinogen as well as aspirin[acetylsalicylic cysteine], 10mg/kg BW orally. Group C: 15 rats receiving the carcinogen as well as aspirin 30 mg/kg BW orally. The rats were sacrificed 32 weeks after the first injection of the carcinogen and their colorectum was examined for macroscopic and microscopic neoplasms. Adenocarcinomas were detected in a 100% of the rats in group A, 100% of the rats in group B, but the incidence was reduced to 50% in the rats of group C [x2, p<0.05]. The number of tumours per animal was 2.1 in group A, 1.57 in group B [ANOVA, p>0.05] and 0.75 in group C [ANOVA, p<0.05]. Conclusion: These data indicate that aspirin suppresses colon carcinogenesis in the dimethylhydrazine-rat model and this protective effect is dose related.