Felis catus ovary as a model to study follicle biology in vitro

Purpose The current study was designed to evaluate the response of individual intact antral follicles from adult female domestic cats to a luteinizing hormone (LH) stimulus in vitro by assessing cumulus-oocyte expansion (C-OE) and steroid production. Methods C-OE and steroid levels (estradiol [E2] and progesterone [P4]) obtained from individual antral feline follicles ( n = 366 follicles; n = 56 cats) were analyzed after 12 or 24 h of culture in the presence or absence of LH (low [3.4 ng/ml] or high [100 ng/ml]). Results At the end of the culture, the highest percentage of expanded cumulus-oocyte complexes (COCs) was observed in the LH groups at 12 or 24 h in comparison to their controls ( p < 0.001). There was a significant increase in expanded COCs when comparing LH concentrations (high vs. low) at 12 or 24 h. Higher levels of both E2 and P4 were observed in the media from antral follicles after 12 and 24 h of culture in the presence of LH (both concentration, p < 0.05). There was no association between hormone levels and follicle diameter; high variability was observed in the steroid levels produced by antral follicles within all treatment groups. Conclusions These data indicate, for the first time, that feline antral follicles (0.5–2 mm) from different stages of the natural estrous cycle can be cultured and will respond to an LH stimulus, based on an increase in steroid levels as well as C-OE after 12 or 24 h in culture.