Effects of follicular fluid components on oocyte maturation and embryo development in vivo and in vitro

Abstract

Oocytes of the antral follicles are bathed in extracellular fluid, which is termed follicular fluid (FF). Follicular fluid is synthesized from a transudate of blood plasma and from secretions of follicular cells. Oocytes in antral follicles persist in meiotic arrest until surge of luteinizing hormone and then start maturation.This suggests that follicular fluid before LH surge might contain meiosis inhibiting factor(s). Hence, inclusion of follicular fluid or cumulus cells or synthesized follicular component(s) during in vitro maturation of oocytes is expected to affect maturation of oocytes and development of the resulting embryos. Follicular fluid components might change during estrous cycle according to follicle size and/or animal nutrition. Concentration of follicular fluid components such as amino acids (AAs), meiosis activating sterol (FF-MAS), hyaluronan (HA), midkine (MK), carotenoids, antioxidants, urea, hormones and others is changed with follicles size and/or animal nutrition and effect on maturation of oocytes and development of the resulting embryos in vivo and/or in vitro. The present review article reviews and discusses these effects.