Bladder and colon lesions in wistar rats submitted to a two-stage Chemical carcinogenesis

• Autor(a) principal: Bononi, Alexandra Procópio
• Data de Publicação: 2022
• Outros Autores: Caetano, Camila da Silva, Rocha, Noeme de Souza, Oliveira, Susie Vieira de, Salvadori, Daisy Maria Fávero, Camargo, João Lauro Viana de
• Tipo de documento: Artigo
• Idioma: por
• Título da fonte: Revista Brasileira de Cancerologia (Online)
• Texto Completo: https://rbc.inca.gov.br/index.php/revista/article/view/2787
• topic: Cancerígenos Químicos; Teste Alternativo; Ratos Wistar; Bexiga; Cólon; Chemical Carcinogens; Alternative Bioassay; Wistar Rats; Colon; Urinary Bladder

This study describes the morphologic lesions that occur in the urinary bladder and colon of Wistar rats submitted to an alternative medium-term multi-organ assay for Chemical carcinogenesis. Developed by Japanese researchers with the Fischer 344 rat strain, in 1996 the bioassay was adopted by the Brazilian Agency for the Environment (IBAMA) as a source of evidence of Chemical carcinogenicity. The animais were allocated to six groups, one of them the non-treated control group. Groups 2, 3 and 4 were initiated for carcinogenesis with N-diethylnitrosamine (DEN, 100 mg/kg i.p.), N-methyl N-nitrosourea(MNU, 80 mg/kg i.p.), N-butyl-N-(4-hydroxybutil)nitrosamine (BBN 0.05 % drinking water, weeks 1 and 2), dimethyl-hidrazine (DMEt, 160 mg/kg, s.c.) and dihydroxi-propyl-nitrosamine (DEIPN 0.1% drinking water, weeks 3 e 4). Promotion of carcinogenesis was accomplished by phenobarbital 0.05% (groups 3 and 5) or 0.01% 2-acetilaminofluorene (2-AAF, groups 4 and 6) mixed in the diet. In the urinary bladder, the most relevant lesion found was the papillary/nodular hyperplasia, which was significantly more frequent in both male groups initiated and promoted for carcinogenesis. Lesions in the colon included aberrant crypt foci (ACF), adenomas and adenocarcinomas. Neoplasia ocurred in every male and female group initiated for carcinogenesis, but a significant incidence of adenocarcinomas occurred only in males also promoted by 2-AAF. The results indicate that the initiation of carcinogenesis was effective in the treated groups and document the lesion patterns that occur in the urinary bladder and colon of Wistar rats.