Fig. 3.

Oocytes after in vitro maturation were removed from co-cultured granulosa cells and denuded mechanically to remove the granulosa cells. Two oocytes matured to the MII stage after 38–42 h of maturation and extruded a polar body of normal morphology (arrow) (a, b), while two other oocytes did not mature in vitro over this time frame (c, d); one oocyte was at the metaphase I (MI) stage (c), and another oocyte continued to express a germinal vesicle (GV) (d). After another 6-h maturation in vitro, the MI stage oocyte matured to the MII stage and extruded a polar body (arrow) (e). The in vitro matured oocytes were of normal dimensions and morphology except for a slightly higher perivitelline space (PS) and thinner zona pellucida (ZP) in comparison to oocytes from the conventional in vitro fertilization procedure after the hormonal stimulation of ovaries (f). (Inverted microscope, magnification 100×). Legend: GV-germinal vesicle, PS-perivitelline space, and ZP-zona pellucida. Red Bar: 50 μm