Objective: In vitro culture and maturation of immature ovarian follicles is an alternative for preserving the fertility potential of young persons using cryopreserved ovarian tissue. The aim of this study was to compare the effect of the mechanical and enzymatic isolation of follicles on the subsequent follicular and oocyte development.Materials and Methods: Preantral follicles were isolated from immature NMRI mice ovaries either mechanically (group M) or enzymatically (group E) and cultured for 10 days. Growth, survival rates of the follicles were assessed during the culture period for both groups. Data were analyzed using the chi-square test.Results: After 2 days of culture, basement membrane disruption had occurred in 36.7% of group M and 100% group E (p<0.05). At the end of culture period the survival rate was higher in group M than in group E (74.3 and 63.55 respectively). Antral formation was observed in 29.5% of surviving follicles in group M and 43.1% of group E (p<0.05).Conclusion: The results indicated the mechanical isolation produces less damage to the preantral follicles than enzymatic isolation and could therefore produce better quality follicles.

Background: Transplantation of cryopreserved follicles can be regarded as a promising strategy for preserving fertility in cancer patients under chemotherapy and radiotherapy by reducing the risk of cancer recurrence. The present study aimed to evaluate whether fibrin hydrogel supplemented with platelet lysate (PL) could be applied to enhance follicular survival, growth, and angiogenesis in cryopreserved preantral follicle grafts. Materials and Methods: Preantral follicles were extracted from 15 four-week-old NMRI mice, cryopreserved by cryotop method, and encapsulated in fibrin-platelet lysate for subsequent heterotopic (subcutaneous) auto-transplantation into the neck. Transplants were assessed in three groups including fresh follicles in fibrin-15%PL, cryopreserved follicles in fibrin-15%PL, and cryopreserved follicles in fibrin-0% PL. Two weeks after transplantation, histological, and immunohistochemistry (CD31) analysis were applied to evaluate follicle morphology, survival rate, and vascular formation, respective-ly. Results: Based on the results, fibrin-15% PL significantly increased neovascularization and survival rate (SR) both in cryopreserved (SR=66. 96%) and fresh follicle (SR=90. 8%) grafts, compared to PL-less fibrin cryopreserved transplants (SR=28. 46%). The grafts supplemented with PL included a significantly higher percentage of preantral and antral follicles. Also, no significant difference was observed in the percentage of preantral follicles between cryopreserved and fresh grafts of fibrin-15% PL. However, a significantly lower (P=0. 03) percentage of follicles (23. 37%) increased to the antral stage in cryopreserved grafts of fibrin-15%PL, compared to fresh grafts (35. 01%). Conclusion: The findings demonstrated that fibrin-PL matrix could be a promising strategy to improve cryopreserved follicle transplantation and preserve fertility in cancer patients at the risk of ovarian failure.