Survival rate of frozen-thawed bovine IVM/IVF embryos in relation to post-thaw exposure time in two cryoprotectants.
The relationship between post-thaw exposure time in cryoprotectants and the viability of in vitro fertilized (IVF)-derived bovine embryos after culture was examined. Good- and excellent-quality Day 7 to Day 8 blastocysts and expanded blastocysts were frozen by the nonstepwise method using 1.6 M propylene glycol (PG) or ethylene glycol (EG) as the cryoprotectant. After the straws were thawed, the embryos were kept in the cryoprotectants for 1, 10, or 30 min. Then the embryos were placed directly into culture medium and washed three times, followed by coculture with cumulus cells. After 48 h of culture, there were no significant differences in survival rate among the various exposure times in PG (79-81%) and EG (71-75%). After 72 h of culture, there were no significant differences among the various exposure times in the fully expanded (PG 76-81%; EG 71-72%), hatching (PG 69-74%; EG 58-71%), and hatched blastocyst rates (PG 60-71%; EG 47-65%). Our findings suggest that different post-thaw exposure times up to 30 min using PG or EG as the cryoprotectant are not harmful to IVF bovine embryos.
Takagi
M
M
United Graduate School of Veterinary Science, Yamaguchi University, Japan.
Otoi
T
T
Suzuki
T
T
D000818:Animals; D002417:Cattle; D002470:Cell Survival; D003451:Cryoprotective Agents / Q000494:pharmacology*; D004622:Embryo, Mammalian / Q000166:cytology / Q000187:drug effects; D019855:Ethylene Glycol; D005026:Ethylene Glycols / Q000494:pharmacology*; D005069:Evaluation Studies as Topic; D005307:Fertilization in Vitro; D011092:Polyethylene Glycols / Q000494:pharmacology*; D013997:Time Factors
D003451:Cryoprotective Agents; D005026:Ethylene Glycols; D011092:Polyethylene Glycols; D019855:Ethylene Glycol