Prospective study.
Academic basic research laboratory.
Ten adult ewes.
Estrus synchronization, controlled ovarian hyperstimulation (COH), ovariohysterectomy; follicular and oviductal oocyte retrieval; IVM of follicular oocytes.
Mean ¡À SD, within-subject (CVw) and between-subject (CVb) variation coefficients of mt activity, intracellular reactive oxygen species (ROS) levels, and mt/ROS colocalization in sheep oocytes from young and aged donors and matured in?vivo (in?vivo MIIs) or in?vitro (IVM MIIs).
Within- and between-subject, in?vivo versus IVM, and age-related variations of mt activity were observed in MII oocytes from hormonally stimulated donor sheep. ROS levels increased significantly in oocytes from aged donors. Mt-ROS colocalization was consistently higher in in?vivo MIIs compared with IVM MIIs. Oviductal energy/antioxidant ability is influenced by COH.
Oocyte energy/oxidative status is affected by within-/between-subject, in?vivo versus IVM, and age-related variations. Mt/ROS colocalization is a reliable marker of in?vivo MII oocytes.