Characterization of isolated late preantral and early antral equine ovarian follicles

Follicles are the functional units of the ovary that contain and support the egg. Depending on the presence of a fluid-filled cavity called an antrum, follicles are developmentally classified as preantral (no antrum) or antral (antrum present). In this study, small preantral and antral horse follicles were removed with needles from ovarian tissue sliced at different thicknesses and classified by their location and other characteristics. The health of the harvested follicles was then examined in several ways (cell survival, toxic by-product levels, and certain types of gene control) to evaluate how slice thickness during follicle removal affects these structures. This study reports, for the first time, that tissue slice thickness influences the removal of late preantral and early antral follicles in horses and that the location of these follicles depends on their developmental stage and quality, with these follicles showing distinct levels of gene control.