In vivo model of colorectal cancer: impact to cigarette smoke exposition on neoplasm development

Our proposal aims to investigate the impact that exposure to cigarette smoke has on the development of lesions in the colorectal mucosa of in vivo model of colorectal carcinogenesis. For that, 24 young male rats were induced to colorectal carcinogenesis and separated into two groups: exposure to cigarette smoke for 20 weeks (DMH+/Tobacco+) and control (DMH+/Tobacco-). In the group (DMH+/Tobacco+), 14.7% dysplasia and 85.29% malignant neoplasms were observed, including tubular adenocarcinoma (73%), carcinoma in situ (17%) and signet-ring cell adenocarcinoma (10%). Mononuclear inflammation and pleomorphisms were mild to moderate. In the control group, there was 7.69% dysplasia, 7.69% tubular adenoma and 84.62% malignant neoplasms, including tubular adenocarcinoma (82%), signet-ring cell adenocarcinoma (9%), carcinoma in situ (5%) and mucinous adenocarcinoma (4%). Mononuclear inflammation and pleomorphisms were moderate to severe. Thus, the experimental model showed that the lesions were predominantly malignant and with histopathological characteristics compatible with human colorectal cancer, including its possible applications for future studies.