Reproduction Abstracts

Oviduct luminal fluid supports early embryo development. The composition this fluid has been debated despite studies using post mortem samples and direct sampling under anesthesia. The routine availability of such data would benefit in vitro embryo culture in addition to our understanding of the influences of maternal physiology on in vivo oviduct fluid composition.

We have devised an in vitro model for the determination of bovine oviduct epithelial cell (BOEC) fluid composition.

BOECs were isolated from reproductive tracts and seeded to the apical fascia of Transwell porous supports at 10⁶ cells/ml. Epithelial disposition (>99%) was confirmed by FACS against CK18. At confluence – confirmed by TEER >700 Ω×cm² – BOECs were maintained in an air–liquid interface for 24 h. The amino acid and glucose in content in the fluid accumulated on the apical fascia, termed in vitro Derived Oviduct Fluid (ivDOF), was analysed. To assess hormonal impact, basal medium was supplemented with 29.4 μM 17β-oestradiol and 6.4 nM progesterone.

17β-oestradiol and progesterone were antagonists for glutamine, phenylalanine, leucine, and lysine secretion (n=6). The concentration of glucose in ivDOF dropped from 2.5 to 1.2 mM following 17β-oestradiol exposure (n=4). Significance was tested by one-way ANOVA coupled with the Holm–Sidak method for overall significance (P<0.05).

A functional model of the bovine oviduct has been developed to study the composition of the luminal environment created in vitro. The results show 17β-oestradiol promoting the establishment of a comparatively hypoglycemic ivDOF microenvironment. This could relate to the subfertile physiology of females with metabolic disorders such as PCOS who ordinarily demonstrate hyperglycemia.