P-255: The Effects of Vanadium in Vitrification Medium on in vitro Maturation of Oocytes Derived from Vitrified-Warmed Mouse Ovary

Background: Since the freezing method was offered, much effort has been done to improve the freezing conditions in different studies and the impact of different freezing methods and mediums on oocyte, embryo and ovarian tissues has been examined. Based on studies, minerals play an important role in oocyte maturation and subsequent embryo development. Vanadium is one of the minerals, which is very important as a trace element for normal cell function as well as development. It has been proven that vanadium can act as an insulin mimicking factor. In this study, the effects of vanadium in vitrification medium on in vitro maturation of oocytes 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 with different concentrations(0,10,100 and 250 μM) of ammonium metavanadat groups. Ovaries in the vitrified groups were frozen sequentially by immersion into two vitrification 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 transported to the straw and were 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 370C. Oocytes derived from ovaries were put in maturation medium for 24h. Results: The results show that the presence of ammonium metavanadate in vitrification solution is effective and can reduce the traumatic effects of vitrification on oocyte in vitro maturation. In addition, viability of oocyte and oocyte maturation 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: Vanadium supplementation of vitrification medium has a positive effect on the in vitro maturation of oocyte.