Abstract
OBJECTIVE: To investigate the action of testosterone (T), isolated or associated with estradiol benzoate (EB), on the proliferation markers and apoptosis of breasts of ovariectomized rats. METHODS: A total of 48 castrated female Wistar rats were divided into 6 groups, and each of them were submitted to one of the following treatments for 5 weeks: 1) control; 2) EB 50 mcg/day + T 50 mcg/day; 3) T 50mcg/day; 4) EB 50 mcg + T 300 mcg/day; 5) T 300 mcg/day; and 6) EB 50 mcg/day. After the treatment, the mammary tissue was submitted to a histological analysis and immunoexpression evaluation of proliferation markers (proliferating cell nuclear antigen, PCNA) and apoptosis (caspase-3). RESULTS: There was a statistically significant difference among the groups regarding microcalcifications and secretory activity, with higher prevalence in the groups treated with EB. There was no difference among the groups regarding atrophy, but a higher prevalence of atrophy was found in the groups that received T versus those that received EB + T. There was a difference among the groups regarding the PCNA (p = 0.028), with higher expression in the group submitted to EB + T 300 mcg/day. Regarding caspase-3, there was no difference among the groups; however, in the group submitted to EB + T 300 mcg/day, the expression was higher than in the isolated T group. CONCLUSION: Isolated T did not have a proliferative effect on the mammary tissue, contrary to EB. Testosterone in combination with EB may or may not decrease the proliferation, depending on the dose of T.