Developmental toxicity of 2-bromoacetamide on peri- and early post-implantation mouse embryos in vitro

2-bromoacetamide (BAcAm), a new class of disinfection by-products (DBPs), is widely detected in drinking water across the world. Reports of the high cytogenetic toxicity of BAcAm have aroused public attention concerning its toxic effects on early embryonic development. In this study, we optimized an in vitro culture (IVC) system for peri-and early post-implantation mouse embryos and used this system to determine the developmental toxicity of BAcAm. We found that exposure to BAcAm caused a reduction in egg cylinder formation rate and abnormal lineage differentiation in a dose-dependent manner. Transcriptomic analysis further revealed that BAcAm exposure at early developmental stages altered the abundance of transcripts related to a variety of biological processes including gene expression, metabolism, cell proliferation, cell death and embryonic development, thus indicating its toxic effects on embryonic development. Thus, we developed a robust tool for studying the toxi-cology of chemicals at the early stages of embryonic development and demonstrated the developmental toxicity of BAcAm in the early embryonic development of mammals.

Automated summary

2-bromoacetamide (BAcAm), a new class of disinfection by-products (DBPs), is commonly found in drinking water worldwide. The high cytogenetic toxicity of BAcAm has raised concerns about its toxic effects on early embryonic development. In this study, we developed an optimized in vitro culture (IVC) system for peri-and early post-implantation mouse embryos and used it to assess the developmental toxicity of BAcAm. We observed that exposure to BAcAm led to a decrease in egg cylinder formation rate and aberrant lineage differentiation in a dose-dependent manner. Transcriptomic analysis further revealed that BAcAm exposure during early developmental stages affected the abundance of transcripts related to various biological processes, indicating its toxic effects on embryonic development. Therefore, this study provides a robust tool for studying the toxicology of chemicals during early embryonic development and highlights the developmental toxicity of BAcAm in mammals.