IN-VITRO DELETERIOUS EFFECT OF HYPOXANTHINE IN HAM NUTRIENT MIXTURE F-10-ASTERISK CULTURE-MEDIUM ON HUMAN OOCYTE FERTILIZATION AND EARLY EMBRYONIC-DEVELOPMENT

Objective: To determine whether hypoxanthine in Ham's Nutrient Mixture F-10 (GIBCO, Grand Island, NY) culture medium affects murine embryo d evelopment or the outcome of patients undergoing IVF-ET. Design: For t he two-cell embryo bioassay, embryos from each female were equally dis tributed and incubated in Ham's F- 10 with or without hypoxanthine sup plementation for up to 72 hours. To assess the effect of hypoxanthine in human IVF-ET, oocytes, sperm, and embryos were cultured in Ham's F- 10 medium with or without hypoxanthine. Fertilization and embryo cleav age were assessed at 18 and 40 hours, respectively, after insemination . Setting: University medical research laboratory. Patients, Participa nts: Nine couples undergoing IVF-ET. Results: Two-cell mouse embryos i ncubated for 24 hours without hypoxanthine developed 40% to morula, co mpared with 6.5% for the hypoxanthine group. At 72 hours, 99.5% of the embryos without hypoxanthine reached the expanded blastocyst stage wi th 65% of them exhibiting hatching, compared with 72% and 19.5%, respe ctively, for the group with hypoxanthine. Human oocytes cultured in Ha m's F-10 without hypoxanthine showed higher fertilization rates than t he group incubated in the presence of hypoxanthine (69% versus 53%). T he proportion of cleaved embryos was not different between the two cul ture media; however, the rate of embryos cleaving without cytoplasmic fragments was significantly higher in the group without hypoxanthine ( 75% versus 35%). Conclusion: Ham's F-10 medium containing hypoxanthine significantly reduced embryo development in the two-cell mouse embryo bioassay. Hypoxanthine in culture medium for IVF-ET may have a delete rious effect on human gametes, leading to decreased fertilization and increased incidence of cytoplasmic fragments in the conceptuses.