2,4,6-triiodophenol exhibits embryotoxicity to pre-implantation mouse embryos in an in vitro exposure model

• Published in: Ecotoxicology and environmental safety 2022-08, Vol.241, p.113745-113745, Article 113745
• Main Authors: Liu, Siya, Feng, Ke, An, Shiyu, Qiu, Jingfan, Zhou, Qing, Yang, Yang
• Format: Article
• Language: English
• Subjects: 2,4,6-triiodophenol; Developmental potency; Embryotoxicity; In vitro culture; Mouse pre-implantation embryos
• ISSN: 0147-6513; 1090-2414
• DOI: 10.1016/j.ecoenv.2022.113745

2,4,6-triiodophenol (TIP), a novel type of halophenolic disinfection byproducts, has been widely detected in water bodies, even in drinking water. Recently, TIP has drawn increasing concerns on account of considerable developmental toxicity towards lower organisms and cytotoxicity for mammalian cells. However, it remains unknown about its toxicity on mammalian pre-implantation embryos. Here, by exposing mouse zygotes derived in vitro fertilization to TIP, which ranged from 5 to 50 μM, we found that TIP impaired the quality of pre-implantation mouse embryos in a dose-dependent manner, inducing decline of both total and trophectoderm cell numbers, enhancing caspase 3/7 activity and reactive oxygen species generation, though it did not decrease blastocyst formation efficiency. For the sake that only high qualified embryos are able to implant in endometrium and generate health body finally, we applied a previously modified in vitro culture system to assess TIP-exposed blastocysts’ further developmental potency beyond pre-implantation stage. Surprisingly, although the exposed dose was only 5 μM and TIP was removed as soon as the zygotes reached blastocyst stage, these blastocysts still nearly lost their implantation and egg cylinder formation ability, exhibiting abnormal embryonic lineage differentiation pattern as well. Therefore, our study not only entirely shows TIP embryonic toxicity on mouse pre-implantation embryos, but also proposes a model to evaluate embryotoxicity from the zygote to egg cylinder stage. [Display omitted] •A novel in vitro model is proposed to entirely evaluate the quality of mouse pre-implantation embryo.•Mouse embryos suffered from TIP exposure formed blastocysts normally with fewer cells.•TIP enhanced caspase 3/7 activity and ROS generation in mouse blastocysts.•TIP impaired developmental potency of blastocysts beyond pre-implantation stage, exhibiting implantation failure, growth arrest and abnormal lineage differentiation.