Bhat M H, Sharma V, Khan F A, Naykoo N A, Yaqoob S H, Khan H M, Fazili M R, Ganai N A, Shah R A
Cryo Letters. 2014 Jan-Feb;35(1):77-82.
Immature oocytes are more sensitive to cold injury than mature oocytes.
The study was to evaluate the post thaw normal oocytes, cleavage and blastocyst rates of ovine cumulus oocyte complexes (COC's) using different cryoprotectants by slow freezing and Open pulled straw (OPS) vitrification.
In five replicates, abattoir derived COC's were collected and distributed into three groups. In Experiment 1, COC's were cryopreserved by a slow freezing protocol using 10% concentration of ethylene glycol (EG), 10% dimethyl sulphoxide (DMSO) or 5% EG and 5% DMSO mixture. In Experiment 2 and 3 embryos were cryopreserved by OPS vitrification using either 33% or 40% (EG, DMSO or an equal mixture of EG and DMSO mixture. Normal oocytes post thaw were in vitro matured and parthenogenetically activated.
Although, there was no difference in the number of post thaw normal oocytes between the groups, cleavage and blastocyst rates were higher in 10% slow freezing group than any of the vitrified groups.
The study demonstrates better cryopreservation of ovine COC's by controlled slow freezing than OPS vitrification.
未成熟卵母细胞比成熟卵母细胞对冷损伤更敏感。
本研究旨在评估采用不同冷冻保护剂，通过慢速冷冻和开放式拉长细管（OPS）玻璃化法冷冻保存绵羊卵丘卵母细胞复合体（COC）后，解冻后正常卵母细胞、卵裂率和囊胚率的情况。
在五次重复实验中，收集屠宰场来源的COC并分为三组。实验1中，采用10%乙二醇（EG）、10%二甲基亚砜（DMSO）或5%EG与5%DMSO混合液的慢速冷冻方案对COC进行冷冻保存。实验2和3中，采用33%或40%（EG、DMSO或EG与DMSO等比例混合液）的OPS玻璃化法对胚胎进行冷冻保存。解冻后的正常卵母细胞进行体外成熟和孤雌激活。
尽管各组解冻后正常卵母细胞数量无差异，但10%慢速冷冻组的卵裂率和囊胚率高于任何玻璃化组。
该研究表明，与OPS玻璃化法相比，采用控制慢速冷冻法对绵羊COC的冷冻保存效果更好。
