Oocyte in vitro maturation (IVM)
Ovaries were obtained from a local slaughterhouse and delivered to the
laboratory within 2 hours. The ovaries were aspirated with a 18-gauge
needle to obtain cumulus-oocyte complexes (COCs) from follicles with
2–8 mm in diameter. The COCs with more than three layers of cumulus
cells and evenly distributed cytoplasm were sorted in the study. For
IVM, the COCs were cultured in chemically defined TCM-199 supplemented
with 0.005 IU/mL FSH (Sigma–Aldrich, Cat. no. F2293), 1 μg/mL
17β-estradiol (Cat. no. E4389), 100 μM cysteamine (Sigma–Aldrich, Cat.
no. M6500), and 10% FBS (Gibco, Cat. no. GIB-16000–044) in a
humidified atmosphere of 5% CO2 at 38.5 °C.