Blastocyst rate and live births from vitrification and slow-cooled two-cell mouse embryos

ObjectiveThe purpose of this study was to develop a closed vitrification system, compare vitrification to a slow-cooled cryopreservation method, and compare the pup rate between both methods using two-cell mouse embryos.DesignRandomized, prospective animal study.SettingHospital-based IVF practice.Animal(s)B6C3F1 mouse embryos.Intervention(s)Two-cell mouse embryos were cryopreserved using a slow-cooled or vitrification method and then thawed at a later date. The embryos were cultured and transferred to recipient females.Main Outcome Measure(s)Embryos were observed for blastocyst rate and pups were observed for phenotypic anomalies and weighed at 30, 60, and 90 days after birth.Result(s)Neither the blastocyst rate, pup rate, nor pup weights were significantly different when the two cryopreservation methods were compared.Conclusion(s)Because there were no differences in blastocyst rates, pup rates, or pup weights, we plan to further investigate the potential effects of vitrification on genotypic damage via the Comet Assay.