Equine oviduct explant culture: a basic model to decipher embryo-maternal communication

Area of Science:

• Reproductive Biology
• Animal Science
• Cell Biology

Background:

• Equine embryos spend 6 days in the oviduct, necessitating an in vitro model for studying embryo-oviduct interactions.
• Analyzing subtle in vivo communication between equine embryos and the oviduct is challenging.
• No previously characterized equine oviduct explant culture model existed for morphological and functional assessment.

Purpose of the Study:

• To establish and characterize a novel in vitro culture system for equine oviduct explants.
• To assess the morphological and functional integrity of equine oviduct explants during a 6-day culture period.
• To validate the utility of this system for investigating horse embryo-maternal interactions.

Main Methods:

• Equine oviduct explants were cultured for 6 days.
• Light microscopy and transmission electron microscopy were used for morphological evaluation.
• Cell viability and apoptosis were assessed.
• Quantitative real-time PCR was employed to analyze hypoxia-related gene expression.

Main Results:

• The culture system successfully maintained equine oviduct epithelial morphology for 6 days.
• Explants exhibited highly differentiated, tall columnar, pseudostratified epithelium with apical cilia, resembling the in vivo state.
• Over 98% of cells remained membrane-intact with less than 2% apoptosis after 6 days.
• Despite some central dark-cell degeneration, key hypoxia-related genes (HIF1A, VEGFA, uPA, GLUT1, PAI1) were not upregulated.

Conclusions:

• The established equine oviduct explant culture system is morphologically and functionally stable for 6 days.
• This system provides a reliable tool for proteome, transcriptome, and miRNome analyses.
• It is an excellent model for unraveling complex embryo-maternal interactions in horses.