Cryopreservation of in vitro produced bovine embryos: effects of lipid segregation and post-thaw laser assisted hatching.
The objective was to determine if lipid segregation, with or without post-thaw laser assisted hatching (LAH) of in vitro produced (IVP) bovine embryos, would enhance in vitro survivability and development 24 h post-thaw. On Day 6 of culture (Day 0 = IVF), in vitro produced bovine embryos were divided into three developmental stages: 32-cell (n = 78), compact morula (CM n = 223), and blastocyst (n =56). Embryos within each stage were allocated to the following treatments prior to cryopreservation in 1.5M ethylene glycol: no treatment (Control), 7.5 μg/mL Cytochalasin B for 20 min (CB), or CB with centrifugation (16,000 × g) for 20 min (CBCF). All CB treatments were extended to include embryo freezing. Immediately post-thaw, one-half of the CBCF and Control groups were subjected to zona pellucida drilling (LAH), using the XY Clone® system, creating groups CBCFLAH and LAH, respectively. All thawed embryos were cultured for 24 h and evaluated. No treatment differences were observed for either post-thaw survival or 24 h development. Within the CM stage, CBCFLAH and LAH exhibited a greater number of both total and live cells than Control (total: 69.4, 69.3, 53.0, live: 56.4, 54.7, 39.3 respectively; P < 0.05). In conclusion, LAH post-thaw alone or in combination with CBCF improved embryo viability following cryopreservation.
Pryor
J H
JH
Ovagenix, Bryan, TX 77805, USA.
Looney
C R
CR
Romo
S
S
Kraemer
D C
DC
Long
C R
CR
D000818:Animals; D002417:Cattle / Q000196:embryology*; D002498:Centrifugation / Q000662:veterinary; D015925:Cryopreservation / Q000662:veterinary*; D003571:Cytochalasin B / Q000494:pharmacology; D046149:Embryo Culture Techniques / Q000662:veterinary*; D004622:Embryo, Mammalian / Q000187:drug effects / Q000502:physiology* / Q000648:ultrastructure; D047108:Embryonic Development; D005260:Female; D005307:Fertilization in Vitro / Q000662:veterinary; D007834:Lasers; D050356:Lipid Metabolism / Q000187:drug effects*; D015044:Zona Pellucida / Q000648:ultrastructure
D003571:Cytochalasin B