Growth and differentiation factor – 9 (GDF-9) increases the in vitro growth rates of isolated goat early antral follicles

Abstract

This study aimed to investigate the effect of growth and differentiation factor 9 (GDF-9) during the in vitro culture of isolated caprine early antral follicles. The isolated and selected early antral follicles were individually cultured for 18 days, and the following treatments were tested: α-MEM+ (control treatment) or α-MEM+ supplemented with 200 ng/mL GDF-9. The following endpoints were evaluated: follicular growth and morphology, estradiol production, oocyte nuclear maturation, and relative expression of key genes related to steroidogenesis (CYP19A1, CYP17, and insulin receptor) and basement membrane remodeling (MMP-9 and TIMP-2). In both treatments, a decrease was observed in the percentage of morphologically intact follicles with a concomitant increase in the rates of extruded and degenerated follicles (P 0.05). Growth and differentiation factor 9 increased the daily growth rate from the first to the second third of culture, with higher values (P 0.05). This study shows for the first time that GDF-9 added to a culture medium increased the follicle growth rate of goat early antral follicles cultured in vitro. Keywords: in vitro culture; antral follicle; goat; GDF-9