Perinatal Exposure to Bisphenol A or Diethylstilbestrol Increases the Susceptibility to Develop Mammary Gland Lesions After Estrogen Replacement Therapy in Middle-Aged Rats.

摘要: The development of the mammary gland is a hormone-regulated event. Several factors can dysregulate its growth and make more susceptible to cellular transformation. Among these factors, perinatal exposure xenoestrogens hormone replacement therapy has been associated with increased risk developing breast cancer. Here, we assessed effects induced by estrogen (ERT) in ovariectomized (OVX) middle-aged rats whether diethylstilbestrol (DES) or bisphenol A (BPA) modified gland. Pregnant were orally exposed vehicle, 5 μg DES/kg/day, 0.5 50 BPA/kg/day from gestational day 9 until weaning. Then, 12-month-old offspring OVX treated 17β-estradiol for 3 months. Morphological changes percentage epithelial cells that proliferated expressed receptor alpha (ESR1) progesterone (PR) analyzed samples 15-month-old animals. ERT lobuloalveolar hyperplasia ductal cysts rats, higher proliferation index cells. Perinatal DES followed number formation fibroadenoma carcinoma situ, without modifying expression ESR1 PR. Also, after months ERT, BPA-exposed had incidence atypical lobular than animals under alone. In conclusion, increases susceptibility develop hyperplastic lesions when confronted later life.