[Breast histologic changes in female rats treated with sex steroids].
OBJECTIVE
To evaluate the association of histologic changes in the breasts of female rats undergoing therapy with sex steroids.


METHODS
An experimental study was conducted of 40 castrated female non-pubertal rats, 20 had given birth (Group B) and 20 had no offspring (Group A). After four weeks, these rats were randomly allocated to subgroups: A1, A2, A3, A4, A5 and B1, B2, B3, B4, B5. Steroids were given to subgroups as follows: A1 and B1--estradiol benzoate; A2 and B2--medroxyprogesterone acetate; A3 and B3--estradiol benzoate and medroxyprogesterone acetate; A4 and B4--tibolone; A5 and B5--placebo. After 10 weeks of treatment, animals were sacrificed and their mammary glands were analyzed. Histologic parameters evaluated were: epithelial cell proliferation, epithelial cells with secretory activity; and cell atypia in terminal duct units and buds or terminal alveoli. The association between microscopic analysis and diverse therapeutic regimens were analyzed by calculating the odds ratio and its respective 95% confidence interval.


RESULTS
Histologic changes were observed in 29 rats: moderate hyperplasia (52.5%), hyperplastic alveolar nodule (42.5%), epithelial atypia (35%), mild hyperplasia (32.5%), secretory activity (20%) and severe hyperplasia (5%). In rats with no offspring when compared to the control, 1.3 times more hyperplastic alveolar nodules were found in the group treated with estradiol, the same was true for moderate hyperplasia in the rats that received medroxyprogesterone acetate, hyperplastic alveolar nodules and epithelial atypia in the group treated with estradiol plus medroxyprogesterone acetate. In the rats with offspring 1.3 times more secretory activity was found with estradiol.


CONCLUSIONS
Epithelial hyperplasia and epithelial atypia with no proliferation are strongly associated to combined therapy with estradiol plus medroxyprogesterone acetate, mainly in the rats without offspring.
Vicelli
José Tadeu
JT
Centro de Atenção Integral à Saúde da Mulher (CAISM) da Universidade Estadual de Campinas (Unicamp) e defendido como Tese de Doutorado pelo Departamento de Tocoginecologia da Faculdade de Ciências Médicas da Unicamp.
Gurgel
Maria Salete Costa
MS
Alvarenga
Marcelo
M
D000818:Animals; D001940:Breast / Q000187:drug effects* / Q000473:pathology; D049109:Cell Proliferation; D003270:Contraceptive Agents / Q000494:pharmacology; D004848:Epithelium / Q000187:drug effects / Q000473:pathology; D020847:Estrogen Receptor Modulators / Q000494:pharmacology; D005260:Female; D012739:Gonadal Steroid Hormones / Q000494:pharmacology*; D006965:Hyperplasia / Q000139:chemically induced / Q000473:pathology; D008325:Mammary Neoplasms, Experimental / Q000139:chemically induced / Q000473:pathology*; D009652:Norpregnenes / Q000494:pharmacology; D011372:Progestins / Q000494:pharmacology; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar
D003270:Contraceptive Agents; D020847:Estrogen Receptor Modulators; D012739:Gonadal Steroid Hormones; D009652:Norpregnenes; D011372:Progestins; C027385:tibolone