Effect of co-culturing with embryonic fibroblasts on IVM, IVF and IVC of canine oocytes

Abstract We studied the effects of mouse embryonic fibroblasts (MEF) and canine embryonic fibroblasts (CEF) on IVM, IVF and IVC of canine oocytes. Cumulus-oocyte complexes were harvested from ovaries by slicing, and in vitro maturation was evaluated in three different conditions: culture media only (control), co-culture with MEF, or co-culture with CEF. The oocytes were cultured for 48 or 72 h. Only oocytes larger than 100 μm in diameter with a homogeneous dark cytoplasm and two or more layers of cumulus cells were used. The culture medium was TCM 199 + 10% fetal bovine serum (FBS) with 100 IU/mL penicillin and 100 μg/mL streptomycin. After 48 h of IVM, the oocytes were fertilized in vitro with fresh canine spermatozoa that had been selected by a swim-up method, and the oocytes and spermatozoa were co-cultured in modified Krebs–Ringer bicarbonate solution (TYH) for up to 20 h in 5% CO 2 in air at 38.5 °C. After insemination, oocytes were transferred to three different conditions (the same as for IVM) and were cultured. After 48 or 72 h of maturation in vitro, the maturation rate of MII oocytes cultured in co-culture of MEF and CEF was higher than for oocytes cultured in control ( P P