Fig. 1
Experimental design. The experimental design included the following experimental groups: a Effects of cryopreservation on GV human oocytes vitrified before and after IVM. Group 1 (G1, Control group): 41 GV-oocytes in vitro matured until MII. Group 2 (G2): 43 GV-oocytes vitrified at GV stage warmed and in vitro matured until MII. Group 3 (G3): 53 GV-oocytes in vitro matured until MII and then vitrified. b Effects of vitrifying solutions (VS) on human oocyte IVM through the intracellular Ca2+ oscillation. In this case, G2 (oocytes vitrified at GV stage) was used as control group. Group 4 (G4): 43 GV-oocytes exposed to vitrification solutions (equilibration solution and vitrification solution from Vitrification Kit media, Irvine®, Denmark) without the subsequent immersion in liquid nitrogen (LN2) and in vitro matured until MII. Group 5 (G5): 41 GV-oocytes exposed to 10 μM ionomycin and in vitro matured until MII. All the MII oocytes obtained were cultured in vitro for 2 h and then parthenogenetically activated in order to assess the oocyte cytoplasmic maturity and viability