体外受精后不同时间收集的牛胚胎的冷冻效果  

Viability of Frozen Bovine Blastocysts Collected at Differ-ent Times after in vitro Fertilization(IVF)

作　　者：阳年生[1] 卢克焕[1] 

机构地区：[1]广西农业大学动物繁殖研究室

出　　处：《中国兽医学报》1995年第3期281-286,共6页Chinese Journal of Veterinary Science

摘　　要：比较了体外受精后不同时间收集的牛囊胚期胚胎冷冻后的存活率。试验一收集受精后第６，７，８和９天出现的胚胎，分３步加入０．７５ｍｏｌ／Ｌ甘油和０．５ｍｏｌ／Ｌ丙二醇，将胚胎装入０．２５ｍＬ细管后，放入已降温至５℃的冷冻机内，立即以２℃／ｍｉｎ的速率降温至－７℃，停留５ｍｉｎ后植冰。植冰后５ｍｉｎ，以０．３℃／ｍｉｎ的速率降温至－２５℃，取出胚胎，并立即投入液氮中保存。解冻时，先让细管在空气中暴露１０ｓ，然后投入２０℃水中。在０．２５ｍｏｌ／Ｌ蔗糖溶液中１０ｍｉｎ稀释防冻剂。经体外培养９６ｈ后，第７天胚胎的存活率最高（７２．７％），显著高于第８天胚胎的存活率（５４．３％，Ｐ＜０．０１）。第６天、第９天胚胎的存活率分别为１８．８％和１８．２％，均显著低于第７天、第８天胚胎的存活率（Ｐ＜０．０１）。试验二用非手术法将２枚第７天或第８天的冷冻胚胎移入处于发情周期第７天的育成母牛子宫内，移植第７天一、二级胚胎的妊娠率分别为２８．１％（９／３２）和２１．６％（８／３７）；移植第８天一、二级胚胎的则分别为３３．３％（７／２１）、１７．６％（６／３４），４组间无显著差异（Ｐ＞０．０５）。４个组的双胚胎率分别为１１．１％（１／９?The viability of frozen bovine embryos collected at different times afterIVF was assessed in the present study.In Exp.1,embryos at the stage from early toexpanded blastocysts were collected on Days 6,7,8 and 9 after IVF of bovine oocytes.They were exposed to 0.75 mol/L glycerol + 0.5 mol/L propylene glycol step by step.After being put in a freezing machine which was pre-cooled to 5℃,they were cooled to-7℃ at the rate of 2℃/min and seeded 5 min later.They were further cooled to -25℃ atthe rate of .3℃/min and plunged into liquid nitrogen.For thawing,the embryos wereexposed to air for 10 s,followed by exposure to water at 20℃ for 1 min.Cryoprotec-tants were diluted out in 0.25 mol/L sucrose solution for 10 min.After cultivation invitro for 96 h,Day 7 embryos showed the highest viability rate(72.7%)which was sig-nificantly higher than that(54.3%)of Day 8 embryos (P<0.01 ).The viability rates ofDay 6 and Day 9 embryos were 18.8%and 18.2%respectively which were significantlylower than those of Day 7 and Day 8 emhryos(P<0.01).In Exp.2,two Day 7 or Day 8frozen-thawed embryos were nonsurgically transferred ipsillaterally to the uterine hornsof heifers on Day 7 of the estrous cycle.The pregnancy rates were 28.1%(9/32), 21.6%(8/37) respectively for Day 7 grade 1 and grade 2 embryos, and 33.3%(7/21 ),17.6%(6/34)respectively for Day 8 grade 1 and grade 2 embryos.There were no sig-nificant differences among the 4 groups(P>0.05).The twinning rates were 11.1%(1/9),12.5%(1/8),0, 0 respectively for the 4 groups (P>0.05).This suggested that thepregnancy and twinning rates were not affected by embryo age and quality grade.

关 键 词：体外受精 囊胚 存活率 妊娠率 冷冻 牛胚胎 

分 类 号：S814.6[农业科学—畜牧学] S823.3[农业科学—畜牧兽医]