Effect of atosiban on rabbit embryo development and human sperm motility

ObjectiveTo investigate embryotoxic potential and effects on human sperm motility of the mixed vasopressin V1a/oxytocin receptor antagonist atosiban considered for novel indication of improvement of uterine receptivity in embryo-transfer recipients.DesignOne-cell rabbit embryo bioassay and human sperm motility bioassay were performed in control media or in media containing atosiban.SettingPrivate center of reproductive medicine and academic research institute of reproduction biotechnology.Animal(s)Rabbit females (New Zealand and California, N = 15) aged 4.5–6.5 months.Intervention(s)In vitro exposure of one-cell rabbit embryos and human sperm to atosiban in the range of therapeutic concentrations clinically occurring in human beings.Main Outcome Measure(s)Embryo development and sperm motility.Result(s)Preimplantation development of one-cell rabbit embryos was not affected by atosiban in the concentrations ≤15,000 nM, which was 50-fold higher than the mean plasma concentration reached during regular therapy (300 nM). Atosiban did not affect human sperm motility in concentrations of ≤3,000 nM, in other words, 10 times the human mean plasma concentration.Conclusion(s)Clinical application of atosiban in the proposed indication may be safe for embryos because it is compatible with preimplantation rabbit embryo development and human sperm motility.