Fertilization and early embryology: Comparison of mouse embryo development in open and microdrop co-culture systems

Co-culture with numerous cell lines has been shown to improve in-vitro embryo development. It is usually performed in open culture without an oil overlay, or in relatively large volumes of medium (e.g. 0.5 ml) under oil. We compared the efficacy of open and microdrop co-culture systems using human endometrial and tubal cell lines and mouse zygotes. Although the mean pH values of the media from the tubal cell cultures (both open and oil-covered) decreased significantly over 5 days of culture, this did not appear to impair embryo development. Both co-culture and microdrop culture significantly improved blastocyst and hatching blastocyst formation rates. The combination of the two techniques (microdrop and co-culture) demonstrated the highest blastocyst formation and hatching blastocyst formation rates, as well as the highest mean cell numbers in hatching blastocysts. Co-culture in a microdrop is a superior system for mouse embryo culture.