Changes of follicular fluid composition during estrous cycle: The effects on oocyte maturation and embryo development in vitro

Abstract

Oocytes are bathed in extracellular fluid of the antral follicles, which is termed follicular fluid (FF). Follicular fluid is synthesized from secretions of theca, granulosa, and cumulus cells and from a transudate of blood plasma. Oocytes persist in meiotic arrest in antral follicles until luteinizing hormone (LH) surge or removal the oocytes from the ovarian follicles. This suggests that FF before LH surge might contain meiosis inhibiting factor(s). The microvasculatory bed of the follicular wall and the composition of FF undergo changes during follicular growth and development, which is important for oocyte maturation and subsequent embryo development. Therefore, it is expected that FF composition and components might change according to timing of FF aspiration from follicles. Hence, negative or positive effects could be expected when FF supplemented during oocyte maturation in vitro. Nutrition effects on microvasculatory bed of follicles and their sizes. Thus, the nutritional status of animals is a factor affected on oocyte maturation and embryo development. The present article reviews and discusses these effects.