In vitro culture and embryo metabolism of cattle and sheep embryos - a decade of achievement.
TL;DR: Compounds such as ethylenediamine tetraacetic acid (EDTA), NaN(3) and 2,4-dinitrophenol have been shown to increase embryo development and quality of resulting embryos, demonstrating that the process of ATP production is a key regulator of in vitro embryo development.
About: This article is published in Animal Reproduction Science.The article was published on 2000-07-02. It has received 199 citations till now. The article focuses on the topics: Embryo culture & Embryo.
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TL;DR: The recent improvements of embryo production and freezing technologies could be used for constitution of flocks without risks of disease transmission and will allow wider propagation of valuable genes in small ruminants populations in the future.
319 citations
TL;DR: Findings indicate that exposure to some in vitro environments during the first 7 days of life can profoundly influence fetal and placental development in cattle.
246 citations
TL;DR: Current literature is reviewed, with emphasis on the bovine model, demonstrating evidence for an effect of post fertilization culture environment on embryo gene expression and quality.
232 citations
TL;DR: It is prudent to not only examine the ability of a culture system to produce a pregnancy with the one or two highest-grade embryos, but also to determine how many embryos from the entire cohort (both fresh and frozen embryos) are capable of producing a live birth.
Abstract: With the growing move in in-vitro fertilization (IVF) clinics to transfer fewer embryos to women, there is an increasing reliance on the IVF laboratory to maximize embryo viability. Subsequently, there is justified scrutiny on the culture system and the media used to sustain the human embryo in vitro. The transfer of fewer embryos to patients also creates an increased dependence on the ability to cryopreserve embryos successfully. Therefore, in addition to the ability of a culture system to produce a single top-quality embryo for transfer, it is also necessary to enhance the cryotolerance of sibling embryos so that they can survive freezing or vitrification. Therefore, when examining which culture media is the best, it is prudent to not only examine the ability of a culture system to produce a pregnancy with the one or two highest-grade embryos, but also to determine how many embryos from the entire cohort (both fresh and frozen embryos) are capable of producing a live birth. Additionally, research on animal models has demonstrated that stress, and the resultant adaptation to conditions during pre-implantation stages, can affect pregnancy loss and fetal growth. It is therefore important to understand the role of each medium component and to identify possible sources of cellular stress to the embryo that will ultimately affect the function and viability of the conceptus.
175 citations
TL;DR: The process of animal production by nuclear transfer is discussed and in particular changes in the methodology which have increased development and survival, simplified or increased robustness of the technique are discussed.
169 citations
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TL;DR: The in-vitro development of 1-cell embryos beyond the 2-cell stage in response to the removal of glucose and the addition of glutamine to the culture medium suggests that glucose may block some essential metabolic process, and that glutamine may be a preferred energy substrate during early development for these mouse embryos.
Abstract: One-cell CF-1 x B6SJLF1/J embryos, which usually exhibit a 2-cell block to development in vitro, have been cultured to the blastocyst stage using CZB medium and a glucose washing procedure. CZB medium is a further modification of modified BMOC-2 containing an increased lactate/pyruvate ratio of 116, 1 mM-glutamine and 0.1 mM-EDTA but lacking glucose. Continuous culture of one-cell embryos in CZB medium allowed 83% of embryos to develop beyond the 2-cell stage of which 63% were morulae at 72 h of culture, but blastocysts did not develop. However, washing embryos into CZB medium containing glucose after 48 h of culture (3-4-cell stage) was sufficient to allow development to proceed, with 48% of embryos reaching the blastocyst stage by 96 h of culture. Exposure of embryos to glucose was only necessary from the 3-4-cell stage through the early morula stage since washing back into medium CZB without glucose at 72 h of culture still promoted the development of 50% of embryos to the blastocyst stage. The presence of glucose in this medium for the first 48 h of culture (1-cell to 4-cell stage) was detrimental to embryo development. Glutamine, however, exerted a beneficial effect on embryo development from the 1-cell to the 4-cell stage although its presence was not required for development to proceed during the final 48 h of culture. Blastocysts which developed under optimum conditions contained an average of 33.7 total cells. The in-vitro development of 1-cell embryos beyond the 2-cell stage in response to the removal of glucose and the addition of glutamine to the culture medium suggests that glucose may block some essential metabolic process, and that glutamine may be a preferred energy substrate during early development for these mouse embryos.
1,119 citations
"In vitro culture and embryo metabol..." refers background in this paper
...Several studies have shown that when in vitro glucose concentrations are higher than in vivo, early embryo development is retarded or Ževen blocked Seshagiri and Bavister, 1989; Chatot et al., 1989; Thompson et al., .1992a ....
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...Until recently, this was generally controlled by reducing the concentration of, or Ž .even removing, glucose within the culture medium e.g. Chatot et al., 1989 ....
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TL;DR: This communication describes the successful culture of one-cell to eight-cell sheep ova and one- cell and eight- cell cattle ova to the morula and blastocyst stages and reports a high embryo survival after transfer of cultured Ova to recipient animals.
Abstract: Fertilized sheep and cattle ova have not been reported to develop readily during culture in vitro. Up to 60% of sheep morulae develop normally during culture (Moor & Cragle, 1971) but earlier cleavage stages undergo limited development (Hancock, 1963; Kraemer, 1966; Tervit & McDonald, 1969; Moore, 1970) and it has been suggested that there is a block to development in vitro at the eightto twelve-cell stage (Wintenberger, Dauzier & Thibault, 1953). Only the early cleavage stages of cattle ova have been cultured and these have not been reported to develop beyond the twenty-four-cell stage in vitro (Thibault, 1966; Brinster, 1968; Sreenan, 1968; Sreenan, Scanlon & Gordon, 1968). This communication describes the successful culture of one-cell to eight-cell sheep ova and one-cell and eight-cell cattle ova to the morula and blastocyst stages and reports a high embryo survival after transfer of cultured ova to recipient animals.
1,009 citations
Additional excerpts
...…Betterbed Ž .and Wright 1985 advocated the use of concentrations of glucose of 5.6 mM and an atmospheric oxygen concentration for the in vitro development of sheep embryos, Ž .whereas Tervit et al. 1972 had advocated a low O tension and energy substrate levels2 based on oviduct concentrations....
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TL;DR: In this review, comparative information on epigenetic regulation of embryo development is discussed, including information on energy substrate and amino acid preferences of embryos and improvements in the design of culture media are discussed, so that higher yields and increased viability of embryos are achieved.
Abstract: Mammalian preimplantation embryos normally develop within the protected environment of the female reproductive tract, which virtually precludes studies on embryogenesis in situ. Information must therefore be derived from experiments on cultured embryos. Consequently, studies on the epigenetic regulation of embryogenesis have long been interwoven with efforts to formulate culture media capable of sustaining normal development. In this review, comparative information on epigenetic regulation of embryo development is discussed, including information on energy substrate and amino acid preferences of embryos. Advantages of simple versus complex culture media, and of substituting serum albumin or synthetic macromolecules for serum, are discussed. Some potential pitfalls of co-culture are described. Culture appears to induce anomalies in embryo metabolism, which may derive from disturbed intracellular pH. Rationales for selecting endpoints to evaluate the outcome of experiments are considered, including incorporation of timing of embryo development into the analysis. Poor experimental design and/or data analysis can detract from or even negate the value of data obtained from embryo culture; examples are examined to help correct this problem. All of these points are discussed with a view to using data on the needs of embryos for making improvements in the design of culture media, so that higher yields and increased viability of embryos are achieved.
868 citations
Additional excerpts
...Ž .fined’’ media Bavister, 1995 ....
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...Bavister, 1995 ....
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Journal Article•
801 citations
TL;DR: This work is supported by an MRC studentship and program grant, respectively, and the authors thank C. C. and M. R. for their support.
745 citations