Low concentrations of bromodichloromethane induce a toxicogenomic response in porcine embryos in vitro

•Low concentrations of BDCM are detrimental to porcine embryo early development.•Genes affected by BDCM exposure during embryo development are compatible with hormonal disruption and cardiac development anomalies.•Porcine embryo is a good in vitro model for risk assessment at environmentally-relevant concentrations.

Bromodichloromethane (BDCM) is one of the trihalomethanes present in chlorinated water. Humans are thus daily exposed. Previous contradictory results failed to clearly establish the adverse effects of low concentrations of BDCM. By using the porcine preimplantation embryo as a sensitive model, we showed that exposure to low concentrations of BDCM (10 and 100 ppb) during the first week of embryo development induced adverse effect on the blastocyst rate and alteration of the estradiol pathway. Our results also suggest that blastocysts exposed to BDCM present transcriptomic and epigenomic adaptive modifications compatible with the cardiac anomalies observed by previous studies of newborns exposed to BDCM during gestation. Thus, phenotypic observations and toxicogenomic adaptations of embryo to low concentration of BDCM provide insights for BDCM risk assessment. Indeed, our results support the use of sensitive toxicogenomic models using environmentally relevant concentrations to which humans are exposed in order to conduct the risk assessment.

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