Liquid helium vitrification of bovine immature oocyte
The effectiveness of liquid helium (LHe), instead of liquid nitrogen (LN2), as cryogenic liquid for open-pulled straw (OPS) vitrification was determined, and the optimal cryoprotectant concentration for LHe vitrification was explored.LN2 and LHe were tested to determine their effect as cryogenic liquid on the vitrification of bovine immature oocytes.Cumulus oocyte complexes (COCs) were divided into three groups,namely, untreated group (control), LN2 vitrified with OPS group, and LHe vitrified with OPS group.Oocyte survival was assessed by morphology, nuclear maturation, and developmental capability.Results indicated that oocytes with normal morphology and developmental capability in the LN2-or LHe-vitrified group decreased compared with the oocytes in the control group (P<0.05).However, the rates of normal morphology, maturation,cleavage, and blastocyst (89.3%, 52.8%, 42.7%, and 10.1%, respectively) in the LHe-vitrified group were all higher than the corresponding rates (79.3%, 43.4%, 34.1%, and 4.7%,) in the LN2-vitrified group (P<0.05).After embryo transfer, normal calves were obtained after the transfer of blastocysts derived from LHe-and LN2-vitrified oocytes.The effects of the different vitrification solutions (EDS30, EDS35, EDS40, EDS45, and EDS50) were examined in LHe vitrification.Bovine immature oocytes were all vitrified by LHe but in different vitrification solutions.No difference was found in the morphology survival rates among the EDS30 (87.9%),EDS35 (90.1%), EDS40 (89.4%), and EDS45 (87.2%) groups (P>0.05).The maturation rate of the EDS35 group(65.0%) was higher than those of the EDS30 (51.3%), EDS40 (50.1%), and EDS45 (52.1%) groups (P<0.05).No significant difference was found in the cleavage and blastocyst rates between the EDS35 (49.0% and 12.1%) and EDS40 (41.7% and 10.2%) groups.However, the rates in the EDS35 group were higher (P<0.05) than those of the EDS30 (36.2% and 6.8%) and EDS45 (35.9% and 5.8%) groups.Thus, the EDS50 groups showed the poorest results.In conclusion, LHe can be used as a cryogenic liquid for vitrifying bovine immature oocytes, and the required concentration of the cryoprotectant needed for LHe vitrification can be reduced from 6.6 M to 5.6 M compared with LN2 vitrification.LHe-vitrified bovine immature oocytes are fully competent in producing blastocysts and developing healthy offspring.
Bovine Immature oocyte Liquid helium vitrification Cryoprotectant concentration
Xueli Yu Hua Wu Xianfei Guo Yakun Xu Wenxia Han Xiaoxia Li Yinghua Li
College of Animal Science and Technology, Henan University of Science and Technology,Luoyang 471003, China;Henan Provincial Key Laboratory for Grass-Feeding Animal, Henan University of Science and Technology, Luoyang 471003, China
国内会议
陕西杨凌
英文
101-110
2015-11-16（万方平台首次上网日期，不代表论文的发表时间）