Table 1.

Development to the blastocyst stage and total blastomere number

Oocyte treatment	n	Blastocyst rate (%)	n	Cell count
Fresh control	67	90.7 ± 1.8a	12	86.8 ± 2.5a
Vitrified Control	92	85.9 ± 1.5a,b	15	58.9 ± 2.5b
Vitrified NAC-Pre	81	79.1 ± 1.8b	12	36.7 ± 2.3c
Vitrified NAC-Post	80	90.1 ± 1.8a,c	12	76.8 ± 4.1d

Development to the blastocyst stage and total cell number of embryos obtained by IVF from fresh or vitrified murine oocytes in presence or absence of NAC. The groups studied were: F-C: oocytes were cultured in KSOM medium for 2 h prior to IVF; V-C: oocytes were cultured in KSOM medium for 2 h prior to vitrification. After warming, oocytes were allowed to recover in KSOM medium for 2 h and subjected to IVF afterwards; V-NAC-Pre: oocytes were cultured in KSOM medium supplemented with 1 mM NAC for 2 h prior to vitrification. Warmed oocytes were allowed to recover for 2 h in KSOM medium before IVF; V-NAC-Post: oocytes were cultured in KSOM medium for 2 h prior to vitrification. Warmed oocytes were allowed to recover for 2 h in KSOM medium added with 1 mM NAC before IVF. Values bearing different letters in the same column differ statistically (p < 0.05); values are expressed as the mean ± SEM.