RESUMO
BACKGROUND: Chronic stress has been investigated as a risk factor for breast cancer. Maternal separation (MS) of rats has been used as a chronic stress model that alters certain systemic functions, such as the immune response. OBJECTIVE: The aim of this study was to determine the possible effect of MS on the development of breast tumors induced by 7,12-dimethyl benzo anthracene (DMBA). METHODOLOGY: postnatal day (PND) 1 female Wistar rats were divided into four experimental groups that either were or were not subjected to MS and either received or did not receive DMBA. For MS, PND 1 to 21 pups were separated from their mothers for 360 min/day. On PND 30, carcinomas were induced in mammary glands using DMBA. Body weight was evaluated, and the injected region was palpated. In addition, the mammary glands were subjected to histological examination, and corticosterone levels were determined in all groups. RESULTS: DMBA-induced groups had significantly lower body weight gain compared with the non-DMBA-induced groups. Maternal separation increased the incidence of preneoplastic changes and breast carcinogenesis in DMBA-treated animals compared with control animals. Corticosterone levels were increased in both DMBA-induced and MS groups without interaction. CONCLUSION: MS is a possible risk factor for DMBA-induced preneoplastic changes and breast tumors in rats.
