Osmotic behavior of in vitro produced bovine blastocysts in cryoprotectant solutions as a potential predictive test of survival.
The osmotic behavior of bovine blastocysts produced in vitro was filmed during exposure to and dilution of cryoprotectant solutions used for vitrification. The relationship between the changes in the diameter of embryos and their subsequent survival was assessed. Embryos collected on Day 6 and Day 7 postinsemination were exposed to 10% glycerol (GLY) for 5 min, 10% GLY + 20% ethylene glycol (EG) for 5 min, and 25% Gly + 25% EG for 30 s, before dilution in 0.85 M galactose and finally in embryo transfer freezing medium (ETF). Embryos that had a higher probability of survival behaved as perfect osmometers, shrinking, reexpanding, or swelling according to an identical pattern, whereas embryos that deviated from this standard usually did not survive. The initial embryo diameter, duration of shrinkage and expansion in 10% glycerol, duration of reexpansion in ETF, and final embryo diameter were clearly predictive of the ability to hatch after culture in vitro. On a given day postinsemination, larger blastocysts were more likely than smaller blastocysts to survive and hatch after exposure to cryoprotectants with or without vitrification.
Kaidi
S
S
Unité des Sciences Vétérinaires, Université de Louvain, B-1348 Louvain-la-Neuve, Belgium.
Donnay
I
I
Lambert
P
P
Dessy
F
F
Massip
A
A
D000818:Animals; D001755:Blastocyst / Q000187:drug effects*; D002417:Cattle; D048429:Cell Size; D015925:Cryopreservation; D003451:Cryoprotective Agents / Q000494:pharmacology*; D004624:Embryo Transfer; D019855:Ethylene Glycol / Q000494:pharmacology; D005307:Fertilization in Vitro; D005690:Galactose / Q000494:pharmacology; D005990:Glycerol / Q000494:pharmacology; D009997:Osmotic Pressure
D003451:Cryoprotective Agents; D019855:Ethylene Glycol; D005990:Glycerol; D005690:Galactose