哺乳动物胚胎冷冻保存技术的研究进展

哺乳动物胚胎冷冻保存效果受冷冻保护剂、冷冻方法、解冻方法等多种因素的影响,其中冷冻方法是一个关键因素.这项技术的应用需要保证胚胎在冷冻和解冻后具有较高的成活率.自1972年小鼠胚胎冷冻保存获得成功以来,许多学者在简化冷冻程序、缩短冷冻时间等方面进行了深入研究.胚胎冷冻保存技术的应用更加广泛,对胚胎生物工程和其他生物技术产生了推动作用.文章对胚胎冷冻保护剂、冷冻方法及冷冻胚胎的解冻等进行了综述.     

影响哺乳动物胚胎冷冻效果的因素分析

影响哺乳动物胚胎冷冻保存的因素很多。本文在总结近１０年来有关胚胎冷冻方面资料的基础上，就胚胎冷冻保护剂，冷冻方法、解冻方法，冷冻保护剂的稀释以及胚胎发育时期等对胚胎冷冻效果的影响进行了探讨。     

不同抗冻剂和冷冻—解冻方法对绵羊胚胎冷冻效果的研究

<正> 前言 到目前为止,国外研究绵羊胚胎冷冻并获得活的后代的有:Moor,N.W.(1976);Willadsen,S.M.(1977);Willadsen,S.M.(1976)。牛、羊胚胎冷冻一解冻后,存活率的变化幅度很大,多数移植成活并发育至产出活仔畜的数量约占全部冷冻胚胎数的35％。 哺乳动物胚胎冷冻过程中,不同抗冻剂配合使用不同的冷冻—解冻方法,对冷冻胚胎解冻后的存活率有明显的影响。目前很多学者对抗冻剂及冷冻和解冻方法进行了大量     

简单而有效的哺乳动物胚胎玻璃化冷冻方法

简单而有效的哺乳动物胚胎玻璃化冷冻方法王海彦朱士恩译１前言如果胚胎可以有效地进行冷冻保存，那么这项技术将可应用在多种哺乳动物如家畜、实验动物、野生动物以及人。然而，在胚胎冷冻和解冻过程中都存在好多会使胚胎受到损伤的因素。如：抗冻保护剂的毒性；冷冻损伤...     

哺乳动物胚胎的冷冻保存

胚胎冷冻保存技术的应用使畜牧业的发展和实验动物的研究发生了很大的变化。本文主要介绍了哺乳动物胚胎冷冻保存的原理、方法、胚胎冷冻／解冻过程中存在的一些问题及其发展趋势。     

哺乳动物胚胎冷冻保存的研究进展

哺乳动物胚胎的超低温保存技术对于动物种质资源的保存和良种家畜的国际交流具有重要意义,是胚胎移植、体外受精、转基因和克隆等胚胎生物技术不可分割的组成部分。1972年,英国学者Whittingham等人首次利用慢速冷冻法保存小鼠胚胎获得成功。此后许多学者对冷冻方法进行了广泛的研究。然而,在胚胎冷冻和解冻过程中都存在许多会使胚胎受到损伤的因素,如:抗冻保护剂的毒性,冷冻损伤,细胞内冰晶的形成,破裂损伤,渗透压引起的膨胀。因此,使用不同的冷冻和解冻法应避免或减少胚胎受到损伤,以提高胚胎解冻后的存活率。1抗冻保护剂和冷冻溶液在哺乳…     

哺乳动物胚胎玻璃化冷冻保存的研究进展

自1985年胚胎玻璃化冷冻(v itrification)保存技术发明以来,玻璃化法先后在小鼠、兔、绵羊、牛、猪、山羊等动物胚胎上获得成功,近年来有关哺乳动物胚胎玻璃化冷冻保存的研究主要集中在冷冻和解冻方法上,相继发明了一些新的玻璃化冷冻方法:冷环玻璃化法(cryo loop)和开放式细管法(open pu lled straw,OPS),并且对解冻后细管内直接脱除防冻剂进行了广泛深入的研究,使得冷冻胚胎移植更易于在生产上推广应用。现将胚胎玻璃化冷冻的原理、冷冻保护剂、冷冻方法、解冻后保护剂脱除方法的最新研究进展作一综述。     

哺乳动物胚胎冷冻保存研究进展

哺乳动物胚胎冷冻保存效果受冷冻保护剂、冷冻方法、解冻方法等多种因素影响,其中冷冻方法是一个关键性因素.目前胚胎冷冻方法主要有常规慢速冷冻法和玻璃化冷冻法两种.常规慢速冷冻法是指利用甘油、乙二醇等做冷冻保护剂通过缓慢降温的方式进行胚胎冷冻;玻璃化冷冻法是指利用高浓度的冷冻保护剂通过快速降温的方式进行胚胎冷冻.与常规慢速冷冻法相比,玻璃化冷冻法简化了操作过程,大大缩短了操作时间,不需昂贵的程序控制冷冻仪.     

冷冻—解冻兔桑椹胚同期和异期移植的成活率

冷冻一解冻胚胎成活力的评价方法有多种,常用的是解冻后的形态学观察和体外培养法,但能够表明其进一步发育能力的最好方法是将其移植入一个假妊娠受体。据报道,冷冻一解冻兔胚胎的移植成活率通常低于非冷冻胚胎。冷冻与非冷冻兔胚胎的这种差异可能是冷冻—解冻胚胎与子宫之间没有同步化所致。冷冻和解冻可延迟胚胎正常代谢和合成作用的恢复。     

牛胚胎冷冻技术的实用化研究

采用不同的冷冻程序，不同的植冰温度，不同的冷冻保护剂，不同的解冻液及不同的解冻方式对牛胚胎冷冻及解冻技术的各个环节进行研究，目的是选择简便，高效的牛胚胎冷冻方法，综合冷冻过程，减少冷冻，解冻中对胚胎的损伤，提高胚胎解冻成活率和移植妊娠率。     

Cryosurvival and pregnancy rates: One‐step protocol for freezing–thawing Shangri‐la Yak (Bos grunniens) Embryos

The yak is one of the most important and economically useful animals for highlanders. The decline in the yak population requires effective measures for the conservation and multiplication of elite germplasm. A standardized protocol will simplify the freezing and warming of yak embryos in straw and facilitate embryo transfer. In this work, we investigated a one‐step protocol that uses a stable basal medium, which comprised a warming medium (1.08 M sucrose) and a freezing medium (EFS40). We also assessed the effects of the new transfer method on embryo survival. A total of 145 yak frozen embryos were thawed in a standard medium system. The one‐step protocol led to a high recovery percentage (84.93) of yak embryos that survived vitrification and warming. The in vitro survival rates of these embryos significantly different from those of embryos frozen–thawed via the conventional method. The 95 embryos frozen–thawed via our one‐step protocol were then implanted in selected recipients. Thirty‐six singleton pregnancies were established. In conclusion, the proposed one‐step method is a simple, safe, and standardized freezing–thawing protocol that ensures embryo survival and quality under field conditions. This study establishes new possibilities for the widespread use of embryo transfer in yaks.     

Methods of conserving gametes and embryos of farm mammalsLes méthoses de conservation des gamètes et embryons de mammifères de fermeKonservierungsmethoden für gameten und embryonen von haus-säugetieren

There are several methods of preserving domestic animal genes. In the present paper methods using frozen germ plasm are considered. Except in the mare, birth rates of more than 50% are obtained from deep-freezing spermatozoa. The freezing of oocytes has not been used yet in all domestic animals, but the techniques of freezing cattle, sheep, goat, rabbit and recently horse embryos are being developed. It is not yet possible to use these techniques in the pig. The success of gene preservation programmes depends not only on the technique used, but also on the efforts made by breeders and official organizations.     

奶牛冷冻胚胎分割和分割后半胚冷冻技术

用简易分割方法,分割奶牛冷冻胚胎16枚,获得半胚32枚,分割成功率为100％(16/16),可移植半胚29枚,移植于16头受体牛,到第3个情期未返情者经直肠检查有6头妊娠,妊娠率为37.5％(6/16)。其中,在分割前或者分割后经恢复培养0.5～2h再移植的10头受体牛,5头妊娠;而未经恢复培养,分割后直接移植的6头受体牛中,只有1头妊娠。移植后3个月,直肠检查确定2头流产。已有1头受体黄牛生出1头奶牛牛犊(母)和1头受体奶牛产1头奶牛牛犊。其余的2头妊娠受体牛将于9月份产犊。此外,用简易分割法分割奶牛胚胎5枚,得到半胚10枚,裸半胚直接冷冻,解冻后回收可移植半胚5枚,移植于4头受体牛,无一头妊娠。结果表明,冷冻胚胎的分割半胚优于分割后冷冻半胚移植效果;冷冻胚胎分割前或者分割后恢复培养移植优于未经恢复培养而直接移植;简易分割法可应用于冷冻胚胎的分割。     

Preservation by deep freezing of oocytes and embryos

Although cryopreservation experiments with mammalian embryos have been performed for more than 30 years, definite progress was only achieved in the seventies. Investigations with mouse embryos have mainly contributed to the establishment of cryopreservation procedures for livestock embryos. Today the freezing of sheep and cattle embryos is applied to practice, but still transfer results range about 10% to 15% below comparable results obtained from transfer with fresh embryos. Procedures for the cryopreservation of mammalian oocytes and subsequent in-vitro fertilization of frozen/thawed oocytes are just being developed. Until now, only in the mouse a reproducable method for this purpose has been found. Meanwhile children were born from human in-vitro fertilization programs after cryopreservation of oocytes as well as embryos, although the cryopreservation of human embryos is facing major ethical objections.     

Coculture of bovine demiembryos prior to freezing.

Pregnancy rates after transfer of frozen/thawed bisected embryos, demiembryos, have until now been very low. In the present study it was attempted to improve the freezability rate of demiembryos by culturing them on a monolayer of bovine oviduct epithelial cells (BOEC) prior to freezing. The cultured frozen/thawed demiembryos showed a lower developmental rate than intact embryos. The pregnancy rate (23%) following transfer was not different from the pregnancy rate after transfer of unfrozen demiembryos (26%). The calving rate (4%), however, was significantly lower than the calving rate after transfer of fresh demiembryos (23%). Although the overall pregnancy rate achieved in this study was low, it can be concluded that a co-culture period upon BOEC prior to freezing does not improve the viability of frozen demiembryos.     

Cryopreservation and In Vitro culture of Preimplantation Embryos in Djungarian Hamster (Phodopus sungorus)

Although embryo cryobanking was applied to Syrian golden and to Campbell's hamsters, no attempt has been made at freezing embryos in Djungarian hamsters. Four‐cell stage embryos were flushed from the reproductive ducts of pregnant females before noon of the third‐day post coitum and frozen in 0.25‐ml straws according to standard procedures of slow cooling. A mixture of permeating (ethylene glycol) and non‐permeating (sucrose) cryoprotectants was used. The thawing was performed by incubating at RT for 40 s followed by 40 s in a water bath at 30.0°C. Most (66.7%) of the non‐frozen four‐cell embryos developed up to the morula stage in rat one‐cell embryo culture medium (R1ECM). The use of hamster embryo culture medium (HECM) yielded fewer morulas (18.2%) during the same 24‐h period of culture. The rate of embryo's surviving the freezing–thawing procedures, as estimated by light microscopy, was 60.7–68.8%. After 24‐h culturing in R1ECM, 64.7% of frozen–thawed four‐cell embryos developed and all of them reached the morula stage. Supplementation of R1ECM with GM‐CSF (2 ng/ml) improved the rate of Djungarian hamster frozen–thawed embryo development: 100% of the four‐cell stage embryos developed, 50% of them achieved the morula stage, and 50% developed even further and reached the blastocyst stage within 24 h of culturing. This study reports the world's first successful transfer of frozen–thawed Djungarian hamster embryos yielding term pups. Taken together, the results of this study demonstrate the possibility of applying some key reproductive technologies, that is, embryo freezing/cryopreservation and in vitro culture, to Djungarian hamsters.     

牛胚胎玻璃化冷冻技术研究进展

胚胎冷冻保存是保存和繁殖遗传优势动物的主要工具,是胚胎移植产业的重要组成部分。目前广泛使用的冷冻方法主要有慢速冷冻和玻璃化冷冻2种。由于玻璃化冷冻具有成本低、效率高、操作简单等优点,玻璃化冷冻法越来越受到人们的重视。经过多年研究,研究人员已经在玻璃化冷冻方法、冷冻液等方面取得了大量进展,玻璃化冷冻法已经开始进入商业化应用。本文综述了牛胚胎冷冻保存技术的研究进展,旨在为相关从业人员提供一定借鉴和参考。     

Effects of resveratrol treatment on mitochondria and subsequent embryonic development of bovine blastocysts cryopreserved by slow freezing

This study evaluated the effects of cryopreservation by slow freezing on the mitochondrial function, DNA integrity, and developmental ability of bovine embryos and examined whether resveratrol treatment of the frozen‐thawed blastocysts improved embryonic viability. In vitro produced bovine embryos were subjected to slow freezing. After thawing, the ATP content and mitochondrial DNA integrity (mtDNA), determined by real‐time PCR targeting short and long mitochondrial sequences, was found to be lower in frozen‐thawed embryos than in fresh embryos, and mtDNA copy number was significantly reduced during the 24‐hr incubation post warming. Furthermore, immunostaining against double‐strand DNA revealed DNA damage in frozen‐thawed embryos. When frozen‐thawed embryos were incubated in the medium containing 0.5 µM resveratrol, SIRT1 expression, and survival rate of the embryos significantly improved compared with the vehicle‐treated embryos. In addition, cell‐free mtDNA content in medium was higher in case of resveratrol‐treated embryos than of vehicle‐treated embryos. In conclusion, slow freezing affects mitochondrial integrity and function in the blastocysts. In the frozen‐thawed embryos, mitochondria were removed during post‐thawing incubation and resveratrol enhanced the process, resulting in improved survivability of the embryos.     

Use of a rapid method of cryopreservation of bovine embryos for non-surgical transfer in transplantation practice

The embryos were frozen and thawed in Cassou minipaillette by a rapid method. Embryos with cryoprotective agent (glycerol, 1.5 M) were placed directly into the freezing medium at the temperature of -6 to -7 degrees C, frozen after seedling at the temperature decrease by 0.3 to 0.5 degrees C per minute to the temperature of -32 degrees C and then transferred directly into liquid nitrogen. They were thawed in a bath warm 20 to 37 degrees C. After thawed the cryoprotective agent was evacuated in 1.1 M sucrose. The best-quality embryos were selected for freezing. Out of these 366 thawed so far, with average survival of 74.31%. The total of the 268 thawed embryos were transferred ipsilaterally, by a non-surgical method, to 190 synchronised heifers, out of which 105 (55.26%) got in calf. Rapid freezing method based on 1.5 M of glycerol and thawing at the presence of 1.1 M sucrose proved effective and suitable for practice, as not only sufficient reviviscence of embryos and their survival in womb are guaranteed, but also a substantial shortening of the freezing as well as thawing process.     

Transfer of frozen-thawed embryos in sheep

Embryos collected from ewes six days after oestrus were frozen in straws using ethylene-glycol as a cryoprotectant. The efficiency of the simplified freezing and thawing procedure was assessed after transfer, which resulted in an overall survival rate of 58.3 per cent. Forty-two lambs were born from 72 frozen embryos which had been transferred without any attempt to evaluate them after the thawing and sucrose dilution process.