Effect of growth factors, EGF and IGF-I, and estradiol on in vitro maturation of sheep oocytes

• Published in: Theriogenology Vol. 54; no. 2; pp. 209 - 218
• Main Authors: Guler, A., Poulin, N., Mermillod, P., Terqui, M., Cognié, Y.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 15.07.2000; Elsevier
• Subjects: Animals; Benzimidazoles - chemistry; Computer Science; development; Epidermal Growth Factor - pharmacology; Epidermal Growth Factor - physiology; Estradiol - pharmacology; Estradiol - physiology; Female; Fertilization in Vitro - veterinary; Fluorescent Dyes - chemistry; follicular fluid; Follicular Fluid - physiology; in vitro fertilization; Insulin-Like Growth Factor I - pharmacology; Insulin-Like Growth Factor I - physiology; Life Sciences; Male; Meiosis - drug effects; Meiosis - physiology; Microscopy, Fluorescence - veterinary; Oocytes - drug effects; Oocytes - growth & development; Oocytes - physiology; ovine; Sheep - physiology; in vitro fertilization; development; ovine; follicular fluid
• ISSN: 0093-691X; 1879-3231
• DOI: 10.1016/S0093-691X(00)00342-3

The objective of these experiments was to determine the effect of exogenous addition of insulin-like growth factor-I (IGF-I, 100 ng/mL), epidermal growth factor (EGF, 10 ng/mL) and estradiol (E2, 100 ng/mL) to the maturation medium of sheep oocytes on their subsequent development in vitro. Addition of IGF-I to the maturation medium did not improve nuclear or cytoplasmic maturation of sheep oocytes at the concentration tested. However, EGF improved significantly the resumption of meiosis (84% oocytes in metaphase II stage after IVM vs. 59% in medium alone). Cleavage rate and blastocyst development rates were improved (P<0.01) after addition of EGF (60% and 29%, respectively), as compared with maturation in TCM 199 alone (39% and 19%, respectively), but remained lower than rates observed after maturation in complete medium containing follicular fluid (FF, 10%) and FSH (81% and 35%, respectively). No additive effect of EGF over FSH was observed during these experiments. Addition of FF to FSH containing maturation medium improved significantly both cleavage (P<0.001) and blastocyst rates (P<0.05). Addition of E2 to the IVM medium is not required when medium already contains FF. However, in defined conditions supplementation of maturation medium with E2 had a positive effect. These results suggest that EGF, FSH and E2 may play an important role in the nuclear and cytoplasmic maturation of sheep oocytes in vitro.