Successful pregnancies after transplantation of frozen–thawed mouse ovaries into chimeric mice that received lethal-dose radiation

ObjectiveTo study whether fecundity was recovered in mice into which umbilical cord blood cells (UCBCs) were transfused after lethal-dose radiation, followed by transplantation of frozen–thawed ovaries.DesignProspective basic research study.SettingAcademic research laboratory.Animal(s)Female C57BL/6 mice as recipients of UCBCs and ovaries, male B6C3F1 mice for mating, and green fluorescent protein (GFP)-transgenic mice: 18.5-day-old fetuses (−/+) for UCBCs and adult GFP mice (+/+) for ovarian tissues.Intervention(s)The UCBCs were transfused into each irradiated mouse, with GFP+ ovaries transplanted 4 weeks later. The chimeric mice were mated 3 weeks after ovarian transplantation and were examined 14 to 16 weeks after the transfusion of UCBCs.Main Outcome Measure(s)Percentage of chimerism, number of GFP+ pups.Result(s)The percentage of chimerism in these mice tends to increase with the radiation dose. The recovery of fecundity was observed in the chimeric mice that were transplanted with fresh and previously vitrified ovaries after exposure to radiation.Conclusion(s)Even when the exposure dose of radiation administered as pretreatment is lethal, the fecundity of recipients can be maintained if their ovaries are cryopreserved before they are exposed to radiation.