Effect of various growth factors on the in vitro development of goat preantral follicles

Abstract

The effect of transforming growth factor-α (TGF-α; 10 ng ml −1), insulin-like growth factor-II (IGF-II; 20 ng ml −1), epidermal growth factor (EGF; 50 ng ml −1) and FSH (1 μg ml −1) was investigated in the in vitro development of goat preantral follicles (PFs). The control medium was bicarbonate buffered Tissue Culture Medium 199 (TCM 199B), without supplementation. Small (40–60 μm) and large (61–100 μm) PFs were cultured for 6 days. In vitro growth of the PFs was assessed by the increase in follicle diameter, oocyte diameter, DNA synthesis by follicular cells and follicular cell number. All growth factors studied induced DNA synthesis in the small and large goat PFs. A significant increase in diameter of the follicles (EGF: 51.18 ± 0.71 versus 58.19 ± 1.41 and FSH: 53.14 ± 0.71 versus 58.30 ± 1.30) and follicular cell number (EGF: 39.21 ± 1.20 versus 55.96 ± 1.32 and FSH: 40.34 ± 1.25 versus 51.75 ± 1.81) was observed in small PFs cultured in EGF and FSH supplemented media. In the large PFs, only EGF induced a significant increase in follicle diameter and follicular cell number. It was concluded that EGF is mitogenic to goat PFs, FSH is capable of inducing growth in small but not large PFs and TGF-α and IGF-II are stimulatory to goat PFs in culture.