Kit ligand decreases the incidence of apoptosis in cultured vitrified whole mouse ovaries

To investigate the development of follicles and incidence of apoptosis in vitrified cultured mouse ovaries in the presence and absence of Kit ligand, 1-week-old mouse ovaries were cultured in the presence or absence of Kit ligand for 7 days. Development and function of ovarian follicles was evaluated by histology and hormonal analysis. Apoptosis assessment was conducted by analysis of DNA laddering, TdT (terminal deoxynucleotidyl transferase)-mediated dUDP nick-end-labelling and caspase-3/7 activity. The proportion of preantral follicles and the level of 17-β oestradiol, progesterone and dehydroepiandrosterone were increased in all cultured groups, and it was significantly higher in Kit ligand treated groups than in the control (P < 0.001). The number of apoptotic signals in both vitrified samples is significantly higher than in the non-vitrified control (P < 0.01), and these signals are significantly lower in both Kit ligand treated groups than in non-Kit ligand treated groups (P < 0.001). The level of caspase-3/7 activity was higher in vitrified cultured ovaries than non-vitrified group (P < 0.01). Kit ligand was shown to improve in-vitro development of follicles, and also acted as an anti-apoptotic factor in vitrified ovaries. The developmental potential of follicles in vitrified groups was lower than that in fresh ovaries.