Poster Presentation ESA-SRB 2023 in conjunction with ENSA

Endocrine disrupting chemicals found in personal care products perturb in vitro mouse blastocyst lineage cell counts and outgrowth areas (#369)

Bethany J Finger 1 , Eve Morano 1 , Alexandra J Harvey 1 , Mark P Green 1
  1. School of BioSciences, University of Melbourne, Parkvile, VIC, Australia

Methylparaben (MeP), triclosan (TCS) and oxybenzone (BP3) are three common oestrogenic endocrine disrupting chemicals (EDCs) found in personal care products associated with negative reproductive health effects. Whether these chemicals can directly impact the pre-implantation embryo is unknown. The aim of this study was to determine how environmentallyelevant concentrations of MeP, TCS and BP3, both individually and in combination, affected mouse in vitro pre-implantation embryo development. Zygotes from 3–4-week-old CBAxC57BL6/J mice were cultured in G-media supplemented with or without EDCs over a range of concentrations found in human urine and serum. Cleavage and blastocyst development rates were recorded on day 5 prior to differential staining to determine inner cell mass (ICM), trophectoderm (TE) and total cell counts. An additional cohort of blastocysts were subjected to a further 96 hours of culture in the presence of individual and combined EDC conditions to quantify trophoblast outgrowth area. No changes in cleavage nor blastocyst rates were evident (P>0.1; n>4 cultures, n>140 zygotes per chemical per concentration). Relative to control embryos, TE and total cell numbers increased following culture with 250 nM MeP (P<0.001), 1500 nM MeP (P<0.05), and 2 nM BP3 (P<0.05). ICM and total cell number decreased in 2 nM TCS (P<0.05). Embryos cultured in both a low and high concentration of combined EDCs displayed decreased ICM:TE ratios (P<0.001). Blastocysts cultured in 250 nM MeP had an increased outgrowth area compared with control blastocysts (P<0.05; n=3 cultures, n>38 blastocysts/group), consistent with the increase in TE cell number on day 5. Thus, environmentally relevant concentrations of common EDCs can directly alter in vitro preimplantation mouse embryo cell numbers and TE outgrowth. Further studies are required to elucidate the exact mechanism of action and the long-term consequences of EDC exposure of the preimplantation embryo.