FTY720 and cyclosporin protect ovarian tissue grafted into rabbits

Objective To determine whether FTY720 combined with CsA has immunomodulatory effects on human ovarian tissue transplanted to the back muscle of rabbits for an 8-week period. Study design We selected rabbits as recipients of ovarian xenografts with and without treatment by CsA and FTY720. Ovarian fragments from twelve patients were cut into 2 mm × 2 mm, 1-2 mm thick pieces and randomly distributed into four groups: Group 1 (FTY720 2 mg/kg/d + CsA 3 mg/kg/d), Group 2 (FTY720 1 mg/kg/d + CsA 3 mg/kg/d), Group 3 (FTY720 0.5 mg/kg/d + CsA 3 mg/kg/d) and Group 4 for control (CsA 3 mg/kg/d). FTY720 was started three days before transplantation and was given daily after transplantation. CsA was administrated post-transplantation. All the animals were killed 8 weeks post- transplantation. Levels of serum estrogen (E 2), interferon-γ (IFN-γ) and interleukin-4 (IL-4) were detected by radioimmunoassay and ELISA. Anti-CD31 and anti-Ki-67 antibodies were used to evaluate neo-vascularization in xenografts and proliferation activity of ovarian follicles. Peripheral CD4+/CD8+ T cells were analyzed by flow cytometry. Results Combined treatment with cyclosporin A and FTY720 improved graft survival and reduced peripheral CD4+ and CD8+ T cell counts compared to treatment with cyclosporin A alone. Neovascularization took place in the peripheral zone of the xenograft while granulosa cells, positively stained by Ki-67, were found in early-stage follicles and stromal cells in the combined treatment groups. Conclusion FTY720 in combination with cyclosporin A maintains human ovarian xenografts in these rabbit models.