P-160: The Effects of Vanadium in Vitrification Medium on In Vitro Growth of Follicles Derived from Vitrified-Warmed Mouse Ovary

Background: Cryopreservation of ovarian tissue is an important option in order to preserve the fertility of cancer patients undergoing chemotherapy and radiotherapy. There are many reports on adding some materials such as calcium, ascorbate and antioxidants to freezing medium. Vanadium is one of the minerals, which is very important as a trace element for normal cell function as well as development. Vanadium, affects enzymes behavior and imitates and regulates the activities of development factors. In this study, the effects of vanadium in vitrification medium on in vitro growth of follicles derived from vitrified-warmed mouse ovary were examined. Materials and Methods: In this study, the ovaries of 2-4 week-old NMRI mice randomly assigned to non-vitrified and vitrifiedwarmed in the presence of different concentrations (0,10,100 and 250 μM) of ammonium metavanadat in vitrification medium. Ovaries in the vitrified groups were frozen sequentially by immersion into two solution, equilibration solution: 7.5% EG, 7.5% DMSO in holding medium (α-MEM+10%FBS) for 7 minutes and vitrification solution: 15% EG, 15% DMSO, 0.5 M sucrose in holding medium (α-MEM+10%FBS) with different concentration of ammonium metavanadate for 3 minutes in room temperature. The ovaries were transported to the straw and kept in a nitrogen tank for a week. After this period, ovaries were transferred to thawing medium with falling concentration of sucrose (1, 0.5, 0.25) at 37°C. After thawing ovaries were examined histologically and then pre-antral follicles with diameter around 100-130 μm mechanically were isolated from ovaries in order to assess the follicle growth and survival rate were cultured for 9 days. Results: The results show that the presence of ammonium metavanadate in vitrification solution is effective and can reduce the traumatic effects of vitrification on ovarian tissues. In addition, follicle growth rate was higher in the presence of 100μM ammonium metavanadate compared to the other vitrified-warmed groups; nevertheless, it was lower than non-vitrified group (ANOVA, p-value<0.05). Conclusion: This study demonstrated that vanadium supplementation of vitrification medium has a positive effect on the follicle growth in follicles derived from vitrified-warmed ovaries.