Immunohistochemical localization of growth factors after cryopreservation and 3 weeks' xenotransplantation of human ovarian tissue

ObjectiveTo compare early follicular growth after fresh and frozen-thawed human ovarian tissue xenografting and to investigate whether expression of c-kit, kit ligand (KL), and growth differentiation factor-9 (GDF-9) is maintained after freezing and xenografting of human ovarian tissue.DesignProspective experimental study.SettingGynecology research unit in a university hospital.Animal(s)Ten nude (Swiss nu/nu) 6-week-old female mice.Intervention(s)The ovarian biopsy samples were obtained from six women, aged 20 to 30 years. Fresh and frozen-thawed ovarian fragments intraperitoneally grafted into nude mice for 3 weeks.Main Outcome Measure(s)Histologic analysis and immunohistochemical evaluation of c-kit, KL, and GDF-9 expression before and after grafting.Result(s)The integrity and proportion of growing follicles increased similarly in both fresh (64%) and frozen-thawed (59%) xenografts compared with non-grafted tissue (fresh: 40%; frozen-thawed: 21%). Both C-kit and KL staining were detected in the oocytes and granulosa cells of preantral follicles, and GDF-9 expression was observed in the oocytes of preantral follicles in all groups.Conclusion(s)Freezing does not appear to have a major impact on early follicular growth after transplantation. This study shows, for the first time, expression of c-kit, KL, and GDF-9 in human preantral follicles after ovarian tissue cryopreservation and xenotransplantation.