Region-specific proteomic changes in the canine oviduct during oocyte maturation following deslorelin-induced ovulation

Abstract

Canine reproductive physiology is unique, with oocytes ovulated at an immature stage and completing meiosis
within the oviduct. This study investigated protein expression in oviductal secretions from the ampulla and isthmus
during oocyte maturation in dogs. Six anestrous female dogs were induced to eestrus using 4.7 mg deslorelin implants,
followed by ovariohysterectomy at various time points. Samples were categorized into four groups (n=3 per group)
based on oviductal region, histological confirmation, and oocyte maturation status. Proteomic analysis revealed regionspecific
protein expression changes linked to oocyte maturation. In the ampulla, PRRG4, RCSD1, and UNC13C were
downregulated, while CFAP54, ACLY, and MCOLN1 were upregulated, indicating roles in energy metabolism,
calcium signaling, and cytoskeletal remodeling. In the isthmus, FCHSD1 and PRKCI were downregulated, while HIC1,
ZMYND11, SORCS3, MEGF6, and DYNLRB1 were upregulated, potentially supporting oocyte quality and fertilization
competence. These findings highlight dynamic proteomic shifts in the oviductal environment during oocyte maturation
in dogs, suggesting the need for further studies to clarify the functional significance of these proteins.