Endocrine function and lymphocyte infiltration of newborn rat ovaries after ultrarapid freezing and allotransplantation

ObjectiveTo evaluate the endocrine function and lymphocyte infiltration of ultrarapidly frozen newborn rat ovaries in adult recipients.DesignAnimal study.SettingReproductive Medicine Laboratory of Ningxia Medical College.Animal(s)Newborn rats within 24 hours after birth and Sprague-Dawley female adult rats.Intervention(s)Newborn or adult rat ovary tissues were cryopreserved with ultrarapid freezing method, using 1.5 M propylene glycol and 0.1 M sucrose as a cryoprotectant agent. After thawing, they were allotransplanted under the kidney capsule of ovariectomized adult female rats to assess the function and the microstructure.Main Outcome Measure(s)Vaginal smear, serum E2 level in recipients, grafts histologic observation, 3β-hydroxy steroid dehydrogenase histochemistry staining, and CD4+/CD8+ T cell immunohistochemistry staining.Result(s)Frozen–thawed newborn rat ovaries survived and established a vascular network with the kidney of recipients. More growing follicles were found in these survival grafts. No significant differences were found in both resumption rates, the day of initiating estrous cycles, and E2 level between the frozen adult and frozen newborn rat ovaries transplant group. Among all the groups, the number of lymphocyte in the frozen newborn rat ovary transplant group is the lowest.Conclusion(s)This is the first report for ultrarapid cryopreservation that can preserve the development potential of immature ovaries in ovariectomized adult recipients and further reduce their immunogenicity successfully.