RESUMO
RESEARCH QUESTION: Is the optimal timing for administering erythropoietin to minimize ischaemic injury in ovarian tissue transplantation before ovary removal for cryopreservation and subsequent transplantation or after transplantation? DESIGN: Thirty Swiss mice (nu/nu) were divided into three groups: treatment control group (nâ¯=â¯10); erythropoietin before harvesting group (EPO-BH) (nâ¯=â¯10) and erythropoietin after transplantation group (EPO-AT) (nâ¯=â¯10). Animals underwent bilateral ovariohysterectomy and their hemiovaries were cryopreserved by slow freezing. At the same time, previously cryopreserved hemiovaries were transplanted subcutaneously in the dorsal region. Erythropoietin (250 IU/kg) and sterile 0.9% saline solution were administered every 12/12 h over 5 consecutive days in the EPO-AT and EPO-BH groups, respectively. RESULTS: Administration of erythropoietin in the EPO-AT group improved the viability of ovarian follicles, reducing degeneration and increasing the number of morphologically normal growing follicles at 14 days after transplantation compared with the EPO-BH group (Pâ¯=â¯0.002). This group also showed higher percentages of proliferative follicles at 7 days after transplantation (P ≤ 0.03), increased blood vessel count (P ≤ 0.03) and greater tissue area occupied by blood vessels at days 7 and 14 after transplantation (P ≤ 0.03), compared with hormone administration before cryopreservation (EPO-BH group) and the treatment control group. Additionally, treatment with erythropoietin before or after transplantation reduced fibrotic areas at 7 days after transplantation (Pâ¯=â¯0.004). CONCLUSION: Erythropoietin treatment after transplantation reduced ischaemic damage in transplanted ovarian tissue, increased angiogenesis, maintenance of ovarian follicle proliferation and reduced fibrosis areas in the grafted tissue.