Xenotransplantation by injection of a suspension of isolated preantral ovarian follicles and stroma cells under the kidney capsule of nude mice

ObjectiveTo develop and test a novel approach to xenotransplantation of isolated preantral follicles underneath the kidney capsule of immunodeficient mice.DesignProspective experimental animal study.SettingAcademic research unit.Animal(s)Healthy adult nude mice.Intervention(s)Bovine ovaries from fetuses (n = 3) and calves (n = 3) were enzymatically disaggregated and subsequently filtered. Isolated preantral follicles were suspended in phosphate buffered saline, and granulosa and stroma cells originating from the ovarian digest served as embedding matrix. The suspension was injected under the kidney capsule of adult nude mice.Main Outcome Measure(s)Fourteen days after transplantation, follicular survival and proliferation in grafts was assessed by histology and proliferating cell nuclear antigen (PCNA) immunostaining, and was compared with ungrafted control tissue.Result(s)Primordial follicles decreased from 58.2% in control tissue to 17.1% in transplants in the fetal group, and from 76.0% to 17.2% in the calf group. Concomitantly, primary follicles increased from 13.4% to 62.2% in the fetal group, and from 5.4% to 63.5% in the calf group. Follicular proliferation measured by PCNA immunolabeling exhibited an increase from 40.6% growing follicles to 81.9% in the fetal group, and from 21.0% to 80.7% in the calf group.Conclusion(s)The massive follicular activation following transplantation indicates that isolated preantral follicles are able to survive and grow 14 days after renal subcapsular xenotransplantation.