Redefining safety standards: A large-scale comparative analysis of bovine versus murine models for medical device embryotoxicity testing.

Structured Abstract Purpose To overcome the limited sensitivity of the standard Mouse Embryo Assay (MEA) for embryotoxicity screening of assisted reproduction devices and to assess the Bovine Embryo Assay (BEA) as a more sensitive alternative. Methods : In a large comparative laboratory study, bovine cumulus–oocyte complexes (from slaughterhouse ovaries) were fertilized with frozen semen from the same bull, and mouse cumulus–oocyte complexes, epididymal sperm, and one-cell embryos were used for MEA. Sperm selection, fertilization, and embryo culture media from two suppliers (A: Vitrolife; B: Genea Biomedx) were tested in parallel using BEA, standard MEA, and an extended MEA including fertilization. BEA assessed cleavage, blastocyst development and kinetics, post-warming re-expansion/hatching, total cell number, ICM and TE allocation, and ICM/TE ratio.