Vitrification of ICSI- and IVF-derived bovine blastocysts by minimum volume cooling procedure: effect of developmental stage and age.
The objective was to investigate the effects of developmental stage (fully-expanded or expanding blastocysts) and/or age (harvested on Days 7 or 8) on post-vitrification in vitro survival of bovine blastocysts derived from intracytoplasmic sperm injection (ICSI) or in vitro fertilization (IVF). Post-warming survival (re-expansion of blastocoele within 24 h) of ICSI-derived fully-expanded blastocysts (80%) was similar to that of their IVF-derived counterparts (88%). However, the ability of ICSI-derived expanding blastocysts to survive vitrification procedures (61%) was lower than that of IVF-derived blastocysts (85%; P < 0.05), although the ICSI- and IVF-derived fresh blastocysts were of similar quality. The age of the blastocysts before vitrification did not affect cryotolerance for either ICSI-derived (73 and 59% for Days 7 and 8 embryos, respectively) or IVF-derived blastocysts (86% for both Days 7 and 8 embryos). At 24 h of post-warming culture, ICSI-derived blastocysts surviving vitrification contained a higher proportion of dead cells than their IVF-derived counterparts (5-13% vs. 2-4%; P < 0.05), but these proportions were not different from those of fresh control embryos. There was an adverse effect of vitrification on the ability of blastocysts to hatch within 72 h of culture only in IVF-derived Day 8 blastocysts (41 and 70% in vitrified and fresh control groups, respectively). In conclusion, the proportion of blastocysts that survived vitrification procedures was similar for ICSI- and IVF-derived bovine blastocysts if the former were cultured to the fully-expanded stage prior to vitrification, with no significant difference between embryos harvested on Day 7 versus Day 8.
Abdalla
H
H
Graduate School of Science and Technology, Shinshu University, Ueda, Nagano 386-8567, Japan.
Shimoda
M
M
Hara
H
H
Morita
H
H
Kuwayama
M
M
Hirabayashi
M
M
Hochi
S
S
D000818:Animals; D001755:Blastocyst; D002417:Cattle / Q000502:physiology; D048429:Cell Size; D002470:Cell Survival; D002478:Cells, Cultured; D002970:Cleavage Stage, Ovum / Q000502:physiology*; D015925:Cryopreservation / Q000379:methods* / Q000662:veterinary; D046149:Embryo Culture Techniques / Q000662:veterinary; D047108:Embryonic Development / Q000502:physiology*; D005260:Female; D005307:Fertilization in Vitro / Q000379:methods / Q000662:veterinary; D005865:Gestational Age; D008297:Male; D011786:Quality Control; D020554:Sperm Injections, Intracytoplasmic / Q000379:methods / Q000662:veterinary; D013696:Temperature