ABSTRACT
Cryopreservation of ovarian tissues and pre-antral follicles is a promising prospect for preservation of women fertility. The aim of this study was to evaluate the in vitro developmental competence of mouse vitrified pre-antral follicles in comparison to isolated pre-antral follicles derived from vitrified ovaries in the presence of alpha lipoic acid [ALA]. Pre-antral follicles derived from fresh, vitrified-warmed ovarian tissues and vitrified-warmed pre-antral follicles were cultured individually with or without ALA, followed by adding hCG to induce ovulation. The follicle growth, oocyte maturation, and embryo development were assessed. The diameter and development of follicles, oocyte maturation and embryo development rates were significantly higher in ALA supplemented groups compared to the respective ALA-free conditions groups. Aforementioned parameters were significantly higher in vitrified-warmed follicles in comparison to follicles derived from vitrified-warmed ovaries. These findings support a superior performance of pre-antral follicles when vitrified rather than when isolated from vitrified ovaries with regard to increasing the rates of developmental parameters. Moreover, ALA improves the in vitro maturation of pre-antral follicles in vitrified and non-vitrified samples.
ABSTRACT
Cryopreservation of pre-antral follicles is a hopeful technique to preserve female fertility. The aim of the present study was to evaluate reactive oxygen species [ROS] and total antioxidant capacity [TAC] levels of mouse vitrified pre-antral follicles in the presence of alpha lipoic acid [ALA]. Isolated pre-antral follicles [140-150 micro m in diameter] were divided into vitrified-warmed and fresh groups. Each group was subjected to in vitro maturation with or without ALA for 12 days, followed by adding human chronic gonadotropin to induce ovulation. In vitro fertilization was performed to evaluate their developmental competence. In parallel, the amount of ROS and TAC were assessed after 0, 24, 48, 72, and 96 h of culture by 2',7'-dichlorofluorescin assay and ferric reducing/antioxidant power assay, respectively. The respective rates of survival, antrum formation, and metaphase II oocytes were significantly higher in ALA-supplemented groups compared to the groups not treated with ALA. TAC and ROS levels were significantly decreased and increased, respectively during the culture period up to 96 h in the absence of ALA in both vitrified and non-vitrified samples. However, with pretreatment of ALA, TAC levels were increased significantly and remained constant up to 96 h in vitrified-warmed pre-antral follicles, while ROS levels completely returned to the level of starting point after 96 h of culture in the presence of ALA. Pretreatment of ALA positively influences development of pre-antral follicles in vitrified and nonvitrified samples through increasing follicular TAC level and decreasing ROS levels