Cryopreservation of goat oocytes and in vivo derived 2- to 4-cell embryos using the cryoloop (CLV) and solid-surface vitrification (SSV) methods.
This study evaluated the efficiency and toxicity of two cryopreservation methods, solid-surface vitrification (SSV) and cryoloop vitrification (CLV), on in vitro matured oocytes and in vivo derived early stage goat embryos. In the SSV method, oocytes were vitrified in a solution of 35% ethylene glycol (EG), 5% polyvinyl-pyrrolidone (PVP), and 0.4% trehalose. Microdrops containing the oocytes were cryopreserved by dropping them on a cold metal surface that was partially immersed in liquid nitrogen. In the cryoloop method, oocytes were transferred onto a film of the CLV solution (20% DMSO, 20% EG, 10mg/ml Ficoll and 0.65 M sucrose) suspended in the cryoloop. The cryoloop was then plunged into the liquid nitrogen. In vivo derived embryos were vitrified using the same procedures. The SSV microdrops were warmed in a solution of 0.3M trehalose and those vitrified with CLV were warmed with incubation in 0.25 and 0.125 M sucrose. Oocytes and embryos vitrified by the SSV method had a significantly lower survival rate than the control (60 and 39% versus 100%, respectively; P<0.05), while the survival rate of CLV oocytes and embryos (89 and 88%, respectively) did not differ from controls. Cleavage and blastocyst rates of the surviving vitrified oocytes (parthenogenetically activated) and embryos (cultured for 9 days) were not significantly different (P>0.05) from the control nor did they differ between vitrification methods. Embryos vitrified with the CLV method gave rise to blastocysts (2/15). Our data demonstrated that the two vitrification methods employed resulted in acceptable levels of survival and cleavage of goat oocytes and embryos.
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Isabelle
I
Nexia Biotechnologies, Inc., 1000 Avenue St.-Charles, Block B, Vaudreuil-Dorion, Que., Canada J7V 8P5.
Bhatia
Bhim
B
Baldassarre
Hernan
H
Dinnyes
Andras
A
Keefer
Carol L
CL
D000818:Animals; D001755:Blastocyst / Q000502:physiology; D002478:Cells, Cultured; D002970:Cleavage Stage, Ovum; D015925:Cryopreservation / Q000295:instrumentation / Q000379:methods / Q000662:veterinary*; D046508:Culture Techniques; D004622:Embryo, Mammalian / Q000502:physiology*; D005260:Female; D006041:Goats; D006358:Hot Temperature; D009028:Morula / Q000502:physiology; D009584:Nitrogen; D009865:Oocytes / Q000502:physiology*; D011247:Pregnancy; D020858:Tissue and Organ Harvesting / Q000662:veterinary
D009584:Nitrogen