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

The research article focuses on creating a viable lab model for studying the interactions between horse embryos and the oviduct, the tube leading from the ovary to the uterus, during the first six days post-fertilization. The researchers were successful in establishing such a culture system that preserved the characteristics of the oviduct tissue for the whole six days.

Model Development

• The researchers technologically advanced a new lab model for studying the interactions at the embryo-oviduct level during the first six days after fertilization.
• This was done by establishing a culture system for equine (horse) oviduct explants – a fragment of tissue obtained from the oviduct.
• This culture system managed to maintain the epithelial morphology i.e. the cellular structure and format of the tissue in question, as confirmed by light microscopy and transmission electron microscopy.

Morphological Characteristic

• The model exhibited a tall columnar, pseudostratified epithelium, very similar to the original in-vivo conditions. This is the lining of the oviduct and its shape and nature is crucial for the interactions that occur.
• The epithelium comes complete with basal nuclei, secretory granules, and apical cilia — additional structures that are characteristic of this type of cell.
• Both epithelial cells and stromal cells that originate from the lamina propria, a layer of loose connective tissue underneath the epithelium, are represented in the explants.

Functional Characteristics

• 98% of the cells in the culture remained membrane-intact — a sign of their health and viability — and fewer than 2% of the cells were apoptotic after six days of culture. Apoptosis is a programmed cell death.
• The researchers did observe some degree of dark-cell degeneration, a type of cell death related to lack of oxygen, in the center of these explants. However, they failed to detect the upregulation of hypoxia-related marker genes. These genes are typically activated and increased in response to oxygen deprivation.

Potential Use

• Because the explant model displayed both morphological and functional integrity, researchers believe it’s an outstanding tool for subsequent studies aimed at investigating the dynamics between horse embryos and the oviduct.
• Displaying stability and ease in setup, this model can be used for proteome, transcriptome, and miRNome analysis – studies of the proteins, RNA, and microRNA produced by the tissue respectively.
• This will help unravel the mystery of embryo-maternal interactions in a horse which have, until now, been difficult to examine.