A mouse embryo culture system for quality control testing of human in vitro fertilization and embryo transfer media and fetal cord sera

Swiss white mice were superovulated, mated, and sacrificed to recover two‐cell embryos that were cultured in Ham's F‐10 supplemented with 15% fetal serum. In 16 experiments, media enriched with fetal bovine serum (FBS) supported blastocyst development from 80% ± 19% (mean ± S.D.) of two‐cell embryos. Culture media + FBS was the positive control when 74 batches of heat‐inactivated human fetal cord serum (hFCS) were tested. Statistical analyses indicated two distinct populations: 49 hFCS promoted blastocyst formation and 25 hFCS grew fewer blastocysts. In five studies, 35/47 two‐cell embryos recovered from mice oviducts in media + FBS and immediately incubated formed blastocysts (75% ± 10%). In six comparison studies where the recovered embryos stood at room temperature for 30 minutes before incubation, only 18/57 (29% ± 21%) became blastocysts. When the colony was housed for 1 week in rooms with Shell No Pest Strips as treatment for mites, only 11/125 two‐cell embryos became blastocysts (9%). In contrast, animals housed in quarters decontaminated with chlorine bleach had reduced breeding efficiency and produced fewer two‐cell embryos. We conclude that (1) Ham's F‐10 + FBS is an excellent positive control to test new batches of hFCS; (2) hFCS that supports blastocyst formation from ≥75% of two‐cell embryos is adequate for human use; (3) pesticide treatment of breeding colonies and cooling of murine embryos during harvest both impaired in vitro blastocyst development; and (4) chlorine bleach cleansing of animal quarters reduced the number of successful matings.