title: Epidermal growth factor-mediated mitogen-activated protein kinase3/1 pathway is conducive to in vitro maturation of sheep oocytes.
abstract: Epidermal growth factor (EGF) has been shown to facilitate the in vitro maturation of sheep oocytes, and enhance embryo's capability for further development. However, such kind of molecular mechanism has not yet been elucidated. In the present study, we investigated the effect of EGF-mediated mitogen-activated protein kinases 3 and 1 (MAPK3/1) pathway on in vitro maturation of sheep oocytes. U0126, a specific inhibitor of MEK (MAPK kinase), was added into the maturation culture medium to block the EGF-mediated MAPK3/1 pathway with different doses. Then, the nuclear maturation of sheep oocytes was examined. Additionally, the effect of EGF-mediated MAPK3/1 on cytoplasmic maturation was examined though in vitro fertilization and embryonic development. The rate of germinal vesicle breakdown (GVBD) after 6 h of culture with 10⁻⁴ mol/l of U0126 (50.4%) was significantly decreased compared with control (67.2%, p < 0.05), and the first polation body (PB1) extrusion rate after 22 h of culture in drug treatment was also significantly inhibited compared with control (28.6% vs. 48.4%, p < 0.05). However, 10-6 mol/l U0126 had slight effect on oocyte nuclear maturation. The normal distribution rate of α-tubulin in the oocytes after 22 h of in vitro maturation was significantly decreased in the 10⁻⁴ mol/l U0126 group (54%) compared with control (68%, p < 0.05). After in vitro fertilization, the cleavage rate in drug treatments (56.8% in 10⁻⁶ mol/l U0126 group and 42.6% in 10⁻⁴ mol/l U0126 group) was significantly decreased compared with control (72.3%, p < 0.01). The blastocyst rate in 10⁻⁴ mol/l U0126 group (17.6%) was also significantly decreased compared with control (29.9%, p < 0.05). Collectively, these results suggest that EGF-mediated MAPK3/1 pathway is conducive to in vitro maturation of sheep oocytes.
authors: Animal Science and Technology College, Beijing University of Agriculture, Beijing, China.
authors: Hemin
authors: H
authors: Ni
authors: Animal Science and Technology College, Beijing University of Agriculture, Beijing, China.
authors: Xihui
authors: X
authors: Sheng
authors: Animal Science and Technology College, Beijing University of Agriculture, Beijing, China.
authors: Xu
authors: X
authors: Cui
authors: Animal Science and Technology College, Beijing University of Agriculture, Beijing, China.
authors: Meichao
authors: M
authors: Gu
authors: Animal Science and Technology College, Beijing University of Agriculture, Beijing, China.
authors: Yunhai
authors: Y
authors: Liu
authors: Animal Science and Technology College, Beijing University of Agriculture, Beijing, China.
authors: Xiaolong
authors: X
authors: Qi
authors: Animal Science and Technology College, Beijing University of Agriculture, Beijing, China.
authors: Shuhan
authors: S
authors: Xing
authors: Animal Science and Technology College, Beijing University of Agriculture, Beijing, China.
authors: Yong
authors: Y
authors: Guo
mesh_terms: D000818:Animals; D002467:Cell Nucleus / Q000187:drug effects; D003593:Cytoplasm / Q000187:drug effects; D047108:Embryonic Development / Q000187:drug effects; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D005260:Female; D005307:Fertilization in Vitro; D059471:In Vitro Oocyte Maturation Techniques / Q000379:methods*; D020935:MAP Kinase Signaling System / Q000187:drug effects*; D019950:Mitogen-Activated Protein Kinase 1 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D009865:Oocytes / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D012756:Sheep; D013997:Time Factors; D014404:Tubulin / Q000378:metabolism
chemical_list: D047428:Protein Kinase Inhibitors; D014404:Tubulin; D004815:Epidermal Growth Factor; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3