Methods
While some female mice were killed 48 h after being injected with equine CG to collect oviducts and prepare OECs, others were killed to recover zygotes after mating with males following superovulation with eCG and hCG. The zygotes obtained were cultured with or without CRH or corticosterone (CRH/Cort) either in Chatot-Ziomek-Bavister (CZB) medium with or without OECs or in conditioned medium (CM) conditioned with OECs pretreated or not with CRH/Cort. Preimplantation development, levels of redox potential and apoptosis, and expression of CRH receptor 1 (CRHR1), glucocorticoid receptor (GR), Fas and 11β-hydroxysteroid dehydrogenase (HSD) were observed in embryos recovered at different times of in vitro culture. After culture of OECs with or without CRH/Cort, levels of redox potential and apoptosis, mRNA and protein expression of growth factors, and protein expression of CRHR1, GR and Fas were examined in OECs and the level of FasL was measured in CM. The gld mice were used to confirm a role for the Fas system in triggering apoptosis of embryos and oviducts. Main