Mohammad Ali Khalili
Mahboubeh Vatanparast
Nahid Yari
Mehdi Mohsenzadeh

Ovarian tissue (OT) cryopreservation is one of the available approaches for fertility preservations among young cancer patients. But it has many side effects such as reduction in the GDF9-β expression and delay in follicular growth. The aim of this study was to evaluate if adding GDF9-β can compensate the reduction of this factor during the freezing process and promote folliculogenesis after transplantation of thawed sheep ovarian tissue! Methods: sheep s OT were frozen and thawed with two methods of freezing; vitrification and slow freezing. Fresh and thawed OTs were transplanted onto the CAM, and they were divided into two groups based on the addition of GDF9-β to the grafted tissue. After 5 days of culture, both histological and immunohistological (Ki-67) assessments were done to evaluate follicular structure, development, and proliferation. The areas of fibrotic and necrotic were measured using MICROVISIBLE software. Results showed that Folliculogenesis took place in all culture groups but was significant only in the + GDF9-β cultured group. Also, better follicular structure preserved in the aforementioned group (p<0.05). More neovascularization (p<0.05) and better transplantation (p> 0.05) took place when GDF9-β was added to the culture medium and the areas of fibrosis and necrosis were lower in this group rather than the control group. Follicularproliferative activity was higher significantly only in the slow freezing GDF9-β cultured group.In conclusion, GDF9-β not only can promote folliculogenesis in the fresh ovarian transplant but also can compensate its reduction during the freezing process and be a stimulatory factor.

GDF9-B, Folliculogenesis, Sheep Ovarian Transplantation, Cryopreservation