Evaluation of apoptosis in long-term culture of vitrified mouse whole ovaries

The purpose of the present study was to investigate the development of follicles and incidence of apoptosis in vitrified neonatal mouse ovaries cultured in vitro in the presence of leukemia inhibitory factor (LIF). The vitrified and non-vitrified ovaries of 1-week-old mouse were cultured in the presence or absence of LIF for 7 days. At the beginning and at the end of culture period in each ovary of all groups of study the mean area and the development of ovarian follicles were analyzed; moreover, the incidence of apoptosis was assessed by transmission electron microscopy, terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labeling (TUNEL) method, DNA laddering and caspase-3/7 activity technique. The hormonal assay was done on the conditioned media collected during culture period. The proportion of preantral follicles and the levels of hormones increased in all cultured groups and it was significantly higher in LIF treated groups than in their control (P < 0.001). The ultrastructural characteristics of cell death, DNA fragmentation and TUNEL positive signals were prominent in vitrified cultured ovaries. The level of caspase-3/7 activity was higher in vitrified cultured ovaries.LIF supplementation during 7 days of culture appeared to significantly preserve cells function and increase the follicular development of both vitrified and non-vitrified ovaries.