Chemical carcinogenesis by DMBA (7,12-dimethylbenzanthracene) in female BALB/c mice: new facts

Abstract

Polycyclic aromatic hydrocarbons are known carcinogens used in rodent experimental models. In this study, the carcinogen DMBA (7,12-dimethylbenzanthracene) was administered by gavage, diluted in corn oil, to female BALB / c mice at hebdomadary doses of 1 mg per animal for 1, 3, 6 or 9 weeks. Animals were weighed and monitored weekly until death. Remaining animals were euthanized at the age of 53 weeks. At necropsy, representative fragments of neoplasms were collected and routinely processed for histopathological analysis. Of all mice that received DMBA, 68.57% developed some type of tumor. Of the 70 mice treated with various doses of DMBA, 22 (31.43%) developed mammary tumors. The adenoacanthoma was the most commonly (18.75%) diagnosed histological type of breast cancer. Lung (15.71%), lymphoid tissue (11.43%), stomach (7.14%) and skin (2.86%) were also primary sites of tumor development. One third (33.33%) of the mice receiving 1 mg of DMBA developed lung cancer. Therefore, the administration of DMBA was shown to be an efficient model of carcinogenesis in mice, especially for the study of breast cancer, when using the highest dose, and lung, when using the lowest dose. Carcinogenesis models have been used for several purposes in cancer research. These results represent new facts for a classic carcinogenesis model. Keywords:Carcinogenesis. DMBA. Mice. Lung neoplasms. Breast neoplasms. ResumoHidrocarbonetos policíclicos e aromáticos são carcinógenos usados em modelos experimentais em roedores. Neste estudo, o carcinógeno DMBA (7,12-dimetilbenzantraceno) foi administrado por gavagem, diluído em óleo de milho, para camundongos BALB/c em doses hebdomadárias de 1 mg por animal por 1, 3, 6 ou 9 semanas. Os animais foram pesados e monitorados semanalmente até a morte. Os animais remanescentes foram eutanasiados com a idade de 53 semanas. Na necroscopia, fragmentos representativos das neoplasias foram colhidos e rotineiramente processados para exame histopatológico. De todos os animais que receberam DMBA, 68,57% desenvolveram algum tipo de tumor. Entre os 70 camundongos tratados com diferentes doses de DMBA, 22 (31,43%) desenvolveram neoplasias mamárias. O adenoacantoma foi o tumor mamário mais comumente diagnosticado (18,75%). Pulmões (15,71%), tecido linfoide (11,43%), estômago (7,14%) e pele (2,86%) foram também locais primários de desenvolvimento de neoplasias. Um terço (33,33%) dos camundongos que receberam 1 mg de DMBA desenvolveram neoplasias pulmonares. Portanto, a administração de DMBA foi considerada um modelo eficiente de carcinogênese em camundongos, especialmente para o estudo de neoplasias mamárias, quando a maior dose é utilizada, e de neoplasias pulmonares, quando utilizada a menor dose. Os modelos de carcinogênese química têm sido usados para diversos estudos na pesquisa em câncer, os resultados aqui apresentados mostram novos fatos para um modelo clássico de carcinogênese.

Phytol as an anticarcinogenic and antitumoral agent: An in vivo study in swiss mice with DMBA‐Induced breast cancer

“…Studies with rodents receiving DMBA (1 mg/animal) during 1st, 3rd, 6th, or 9th week of treatment show that most (68%) histopathological changes, indicating this model as an important method to study carcinogenesis, which explains why doses of 1–3 mg are efficiently used in rodents to induce cancers . Indeed, DMBA is a carcinogenic chemical that requires metabolic activation in the liver and mammary gland .…”

Citrinin against breast cancer: A cytogenotoxicological study

“…Our findings showed that DMBA causes breast enlargement, which was reduced with the CPA and CIT therapies. DMBA (1–20 mg/animal, single dose) for 6–13 weeks can cause mammary tumors in 75–100% experimental animals (Alencar et al, 2019; Currier et al, 2005; Oliveira et al, 2015). Our histopathological results suggest that DMBA (6 mg/kg/week) at the 11th weeks induced significant mammary carcinoma in the right breast of female mice.…”

“…(1-20 mg/animal, single dose) for 6-13 weeks can cause mammary tumors in 75-100% experimental animals (Alencar et al, 2019;Currier et al, 2005;Oliveira et al, 2015) (Sanchez-Diaz et al, 2008). CIT also induces genotoxicity (Bouslimi et al, 2008) and CA (Kuroda et al, 2013).…”

Use of thermography in skin grafts after the application of therapeutic ultrasound in Wistar rats

“…Carcinogenesis induction was performed by single intradermal application of 0.5% DMBA (7,12-dimethylbenzanthracene, Sigma-Aldrich, USA) diluted in acetone to the skin of the dorsal region of the thorax, 3 cm in the caudal direction to the first cervical vertebra, as described by Oliveira et al 13 . Due to the safety of the team, the procedure was performed in a laminar flow chamber, with the use of individual protection (PPE).…”