In utero and lactational exposure to an environmentally relevant mixture of brominated flame retardants induces a premature development of the mammary glands

Gouesse, Rita; Dianati, Elham; McDermott, Alec; Wade, Michael G.; Hales, Barbara; Robaire, Bernard et Plante, Isabelle ORCID: https://orcid.org/0000-0003-2080-6450 (2021). In utero and lactational exposure to an environmentally relevant mixture of brominated flame retardants induces a premature development of the mammary glands Toxicological Sciences , vol. 179 , nº 2. pp. 206-219. DOI: 10.1093/toxsci/kfaa176.

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Résumé

In utero and prepubertal development of the mammary glands occurs minimally in a hormone independent manner until puberty where maturation of the hypothalamic-pituitary-gonadal axis drives an extensive remodeling. Nevertheless, because the immature glands contain functional hormone receptors, they are especially vulnerable to the effects of endocrine disruptors, such as brominated flame retardants (BFRs). BFRs are widespread chemicals added to household objects to reduce their flammability, and to which humans are ubiquitously exposed. We previously reported that in utero and lactational exposure to BFRs resulted in an impaired mammary gland development in peripubertal animals. Here, we assessed whether BFR-induced disruption of mammary gland development could manifest earlier in life. Dams were exposed prior to mating until pups' weaning to a BFR mixture (0, 0.06, 20, or 60 mg/kg/day) formulated according to levels found in house dust. The mammary glands of female offspring were collected at weaning. Histo-morphological analyses showed that exposure to 0.06 mg/kg/day accelerates global epithelial development as demonstrated by a significant increase in total epithelial surface area, associated with a tendency to increase of the ductal area and thickness, and of lumen area. Significant increases of the Ki67 cell proliferation index and of the early apoptotic marker cleaved caspase-9 were also observed, as well as an upward trend in the number of thyroid hormone receptor α1 positive cells. These molecular, histologic, and morphometric changes are suggestive of accelerated pubertal development. Thus, our results suggest that exposure to an environmentally relevant mixture of BFRs induces precocious development of the mammary gland. © 2020 The Author(s) 2020. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Type de document:	Article
Mots-clés libres:	In Utero and Lactational Exposure; Apoptosis; Brominated Flame Retardants; Endocrine Disruptors; low-Dose Effects; Mammary Gland; Precocious Development; Proliferation; Thyroid Hormone Receptor
Centre:	Centre INRS-Institut Armand Frappier
Date de dépôt:	22 juin 2022 19:32
Dernière modification:	31 déc. 2023 05:00
URI:	https://espace.inrs.ca/id/eprint/12338

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