Perinatal exposure to bisphenol-A alters peripubertal mammary gland development in mice.
Developmental exposure to estrogenic chemicals induces morphological, functional, and behavioral anomalies associated with reproduction. Humans are exposed to bisphenol-A (BPA), an estrogenic compound that leaches from dental materials and plastic food and beverage containers. The aim of the present study was to determine the effects of perinatal exposure to low, environmentally relevant doses of BPA [25 and 250 ng BPA/kg body weight (bw).d] on the peripubertal development of the mammary gland. BPA exposure enhanced the mammary glands' sensitivity to estradiol in ovariectomized CD-1 mice. In their intact 30-d-old littermates, the area and numbers of terminal end buds relative to the gland ductal area increased whereas their apoptotic activity decreased. There was a positive correlation between ductal length and the age at first proestrus; that was reduced as the BPA dose increased, suggesting that BPA exposure slows down ductal invasion of the stroma. There was also a significant increase of progesterone receptor-positive ductal epithelial cells that were localized in clusters, suggesting future branching points. Indeed, lateral branching was significantly enhanced at 4 months of age in mice exposed to 25 ng BPA /kg bw.d. In conclusion, perinatal exposure to environmentally relevant BPA doses results in persistent alterations in mammary gland morphogenesis. Of special concern is the increased terminal end bud density at puberty as well as the increased number of terminal ends reported previously in adult animals, as these two structures are the sites at which cancer arises in humans and rodents.
Muñoz-de-Toro
Monica
M
Department of Anatomy and Cellular Biology, Tufts University School of Medicine, 136 Harrison Avenue, Boston, Massachusetts 02111, USA.
Markey
Caroline M
CM
Wadia
Perinaaz R
PR
Luque
Enrique H
EH
Rubin
Beverly S
BS
Sonnenschein
Carlos
C
Soto
Ana M
AM
D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn; D017209:Apoptosis / Q000187:drug effects; D001559:Benzhydryl Compounds; D002455:Cell Division / Q000187:drug effects; D004781:Environmental Exposure; D004958:Estradiol / Q000494:pharmacology; D047628:Estrogen Receptor alpha / Q000378:metabolism; D004968:Estrogens, Non-Steroidal / Q000494:pharmacology*; D005260:Female; D015870:Gene Expression / Q000187:drug effects; D008321:Mammary Glands, Animal / Q000166:cytology / Q000187:drug effects* / Q000254:growth & development*; D051379:Mice; D008815:Mice, Inbred Strains; D010636:Phenols / Q000494:pharmacology*; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D011518:Proto-Oncogene Proteins / Q000235:genetics; D011980:Receptors, Progesterone / Q000378:metabolism; D012741:Sexual Maturation / Q000187:drug effects*; D051153:Wnt Proteins; D060528:Wnt4 Protein; D000098826:Bisphenol A Compounds
D001559:Benzhydryl Compounds; D004958:Estradiol; D047628:Estrogen Receptor alpha; D004968:Estrogens, Non-Steroidal; D010636:Phenols; D011518:Proto-Oncogene Proteins; D011980:Receptors, Progesterone; D051153:Wnt Proteins; D060528:Wnt4 Protein; C555581:WNT4 protein, human; C555582:Wnt4 protein, mouse; C006780:bisphenol A; D000098826:Bisphenol A Compounds