Effects of in utero exposure to benzophenone-3 in pubertal murine mammary gland

SCHIERANO-MAROTTI G; ALTAMIRANO GA; GOMEZ AL; MUÑOZ-DE-TORO M; RODRIGUEZ HA; KASS L

Modalidad Virtual

Congreso; Reunión Anual de Sociedades de Biociencias; 2020

Sociedad Argentina de Investigación Clínica

Benzophenone-3 (BP3), an ultraviolet radiation filter commonly used in sunscreens and other personal care products, has shown endocrine disrupting properties. Our aim was to evaluate whether in utero exposure to BP3 alters mammary gland (MG) development during puberty. Pregnant C57BL/6 mice were dermally exposed to vehicle (sesame oil; Control), 0.15 (0.15B) or 50mg BP3/kg/day (50B) from gestation day 8.5 to 18. Gestational parameters such as the length of gestation, the weight gain of dams and the number of pups per litter were recorded. Also, the offspring body weight (BW) gain during lactation was evaluated. After weaning, the onset of puberty in females was recorded as the day of vaginal opening. MG samples were obtained in diestrus on postnatal day 45. Total and epithelial area, perimeter, longitudinal growth, branching and number of terminal end buds (TEBs) were measured in MG whole-mounts (WMs), whereas MG morphology was analyzed in histological sections. The expression of Ki-67, estrogen receptor and progesterone receptor (PR) was evaluated by immunohistochemistry. The gestational parameters in the dams, as well as the BW gain and the onset of puberty in the female offspring were similar between groups. Histo-morphological analysis showed similar MG growth between groups, with ducts extending beyond the lymph node, ductal-side branching and TEBs. The proliferation index (Ki-67) and the expression of steroid hormone receptors were similar in all groups. However, in animals exposed to BP3, PR-positive cells were observed in clusters in MG ducts, suggesting future branching points. Although in utero exposure to BP3 induces limited changes in the female mammary gland at puberty, these changes could be associated with mammary ductal branching and an acceleration of its development.