Comparison of in vitro culture of preantral follicle isolated from vitrified-warmed mouse ovaries with fresh follicles in culture media

Vitrification is a simple and ultra rapid technique for the conservation of fertility. In this study, we compare the in vitro development of preantral follicles obtained from fresh specimens with vitrified- warmed mouse ovaries. This experimental study was carried out on 20, 14-day-old female mice (NMRI). Ovaries were vitrified with a solution containing ethylene glycol, ficoll 70 and sucrose in PB1 (EGFS40) for 5 min, and transferred directly into liquid nitrogen and stored for one week. Fast warming was done by descending sucrose at room temperature. Preantral follicles with 100-130 µm in diameter were mechanically isolated from fresh and vitrified-warmed ovaries and cultured in α-minimum essential medium (α-MEM) supplemented with 5% fetal bovine serum (FBS), 100 mIU/ml rFSH, 1% ITS, and 20ng/ml mrEGF in vitro for 10 days. Diameter of follicle, and, survival rate and number of antral follicles in both groups were compared using t-test and chi-square test, respectively. Isolated follicles from the vitrified and nonvitrified groups survived and grew in vitro culture. On the day 6 survival rates in the vitrified and fresh control groups were 72.1% and 78.6%, and, on the day 10, they were 66.9% and 72.6%, respectively. Follicle antrum formation was 37.5% in the vitrified group while it was 43.5% in the fresh group in the 10th day. On the day 2, the mean diameters of fresh and vitrified follicles were 158.11 ± 11.23 and 155.48 ± 8.35 and on the day 4, they were 201.56 ± 9.87 and 193.42 ± 8.46, respectively. There was no significant difference between the control and vitrified groups in these variables (p>0.05). Taken together, cryopreservation of the ovary by vitrification seems to be a promising method to preserve ovarian follicles.