Xenotransplantation of human ovarian tissue pieces in gonadotropin-stimulated SCID mice: the effect of ovariectomy.

The number of follicles were compared in different developmental stages after the cryopreservation of human ovarian tissue by open freezing system followed by xenotransplantation into severe combined immunodeficient (SCID)-mice under stimulation, with and without ovariectomy. Ovarian tissue, cryopreserved for fertility preservation was partly examined by LIVE/DEAD viability staining or was transplanted in the neck muscle of 32 SCID-mice. The development of follicles, estradiol production, vaginal cytology and uterus weight was assessed after 15 weeks under gonadotropin stimulation, with or without ovariectomy. Viable follicles were detected in all frozen/thawed specimens using the LIVE/DEAD assay. Ovariectomy caused a significant improvement of survival of follicles in the preantral and antral stages in the gonadotropin-stimulated animals (p < 0.001), whereas there was no significant effect on the primordial and primary follicle counts. In the non-ovariectomised group, only isolated primordial and primary follicles could be detected. The total follicle amount was significantly higher in the ovariectomised group (n=17, 9.2 +/- 7.8, mean +/-SD) than in the non-ovariectomized group (n=15, 0.3 +/- 1.0). This study demonstrates that ovariectomy of stimulated recipient SCID-mice is essential for the development of follicles after xenotransplantation of cryopreserved human ovarian grafts.