Spermatozoa interaction with the oviduct epithelium prolongs the longevity of the sperm. Binding of sperm to the oviduct epithelium results in sperm quiescence and prevention of premature capacitation. However, the mechanisms of this phenomenon remain enigmatic. In order to study sperm-oviduct epithelial cell (OEC) interactions in vitro, an appropriate OEC culture reflective of in vivo cells was necessary. Generally cultured epithelial cells will undergo some degree of dedifferentiation resulting in the loss of key morphological and consequently, functional features of the cells. Therefore, it was pivotal to establish a method for the culturing of polarised OEC within the horse, which has been previously absent.

To stimulate cell polarisation, monolayers were established in an air-liquid interface on porous polycarbonate membrane inserts in a highly supplemented culture medium of DMEM:Ham’s F-12 with 10% FBS, EGF, insulin, transferrin and selenium. The epithelial origin of monolayer cultures was confirmed by anti-cytokeratin immunofluorescence. Positive gene expression of progesterone receptor (PGR) confirmed the functional competence of the OEC monolayers. Monolayers were able to maintain a differentiated structure as evident by tightly compacted bulbous shaped cells, with cilia and microvilli present on the apical surface displayed by scanning electron microscopy. Furthermore, cultures were capable of binding stallion spermatozoa. Interestingly, when this method of OEC culturing was applied within the bovine, heterologous binding was found between stallion spermatozoa and bovine OEC. Prior to this study the establishment of a polarised OEC culture within the horse was not well established. The method developed within this study has shown its competence for use as an appropriate in vitro model for the further study of sperm-OEC interactions and on top of this, non-species-specific interactions between sperm and OEC were observed.