Embryonic disc development and subsequent viability of cattle embryos following culture in two media under two oxygen concentrations

2004 ◽  
Vol 16 (8) ◽  
pp. 787 ◽  
Author(s):  
A. E. Fischer-Brown ◽  
B. R. Lindsey ◽  
F. A. Ireland ◽  
D. L. Northey ◽  
R. L. Monson ◽  
...  
Keyword(s):  
Oxygen Concentration ◽  
Latin Square ◽  
Bovine Embryos ◽  
Morphological Evaluation ◽  
Embryonic Disc ◽  
Developmental Capacity ◽  
Series Of Experiments ◽  
Oxygen Concentrations

Bovine embryos were produced in vitro using a 2 × 2 design of modified medium (KSOM or SOF) and oxygen concentration (5% or 20%). Day 7 blastocysts were transferred in bulk (n = 11, on average) to recipient heifers and recovered non-surgically at Day 14. In two replications of a Latin square, eight heifers received embryos from each combination of factors. Recovered embryos were evaluated for trophoblast length and width, as well as the presence and diameter of an embryonic disc (ED). An ED was detected in a higher percentage of embryos that had been cultured in KSOM than SOF (72% v. 46%, respectively; P < 0.05). The aim of a second series of experiments was to associate Day 14 morphology with subsequent developmental capacity. In vitro-produced blastocysts were transferred (n = 17–20) on Day 7 to each of eight heifers and recovered at Day 14. Thirty-eight blastocysts were retransferred to heifers following morphological evaluation. Embryos in which an ED with no signs of degeneration had been detected maintained more pregnancies than other embryos in which an ED had either shown signs of degeneration or had not been detected (5/8 v. 2/30, respectively; P < 0.01). Further investigation into ED integrity at the elongating stage may contribute to our understanding of pregnancy establishment and maintenance.

scholarly journals The FLASH effect depends on oxygen concentration

2020 ◽  
Vol 93 (1106) ◽  
pp. 20190702 ◽  
Author(s):  
Gabriel Adrian ◽  
Elise Konradsson ◽  
Michael Lempart ◽  
Sven Bäck ◽  
Crister Ceberg ◽  
...  
Keyword(s):  
Oxygen Concentration ◽  
Underlying Mechanism ◽  
Oxygen Depletion ◽  
Therapeutic Window ◽  
High Dose ◽  
Dose Rates ◽  
Conventional Dose ◽  
Oxygen Concentrations

Objective: Recent in vivo results have shown prominent tissue sparing effect of radiotherapy with ultra-high dose rates (FLASH) compared to conventional dose rates (CONV). Oxygen depletion has been proposed as the underlying mechanism, but in vitro data to support this have been lacking. The aim of the current study was to compare FLASH to CONV irradiation under different oxygen concentrations in vitro. Methods: Prostate cancer cells were irradiated at different oxygen concentrations (relative partial pressure ranging between 1.6 and 20%) with a 10 MeV electron beam at a dose rate of either 600 Gy/s (FLASH) or 14 Gy/min (CONV), using a modified clinical linear accelerator. We evaluated the surviving fraction of cells using clonogenic assays after irradiation with doses ranging from 0 to 25 Gy. Results: Under normoxic conditions, no differences between FLASH and CONV irradiation were found. For hypoxic cells (1.6%), the radiation response was similar up to a dose of about 5–10 Gy, above which increased survival was shown for FLASH compared to CONV irradiation. The increased survival was shown to be significant at 18 Gy, and the effect was shown to depend on oxygen concentration. Conclusion: The in vitro FLASH effect depends on oxygen concentration. Further studies to characterize and optimize the use of FLASH in order to widen the therapeutic window are indicated. Advances in knowledge: This paper shows in vitro evidence for the role of oxygen concentration underlying the difference between FLASH and CONV irradiation.

Comparative study on amplification methods dedicated to gene profiling during trophoblast expansion in bovine embryos

2003 ◽  
Vol 2003 ◽  
pp. 75-75
Author(s):  
S. Degrelle ◽  
I. Hue ◽  
J-P. Renard
Keyword(s):  
Comparative Study ◽  
In Vitro Transcription ◽  
Gene Profiling ◽  
Bovine Embryos ◽  
Embryonic Disc ◽  
Somatic Tissues ◽  
Set Up ◽  
Implantation Period

In bovine conceptuses, the trophoblast elongates rapidly from the 13th to the 19th day of pregnancy, while the embryonic disc differentiates to set up the primary germ layers and the axis of the fetus. Observations on pregnancies of cloned fetuses underline placental abnormalities which could originate from earlier gene deregulations occurring during this long pre-implantation period. To allow screenings with individual trophoblasts we used amplification protocols involving either PCR or in vitro transcription steps. For that purpose we used a bovine-specific macro-array starting from a cDNA library generated on early in vivo elongating conceptuses. RNAs from adult somatic tissues were used to compare hybridisation patterns generated with amplified and unamplified polyA+ probes.

scholarly journals 221 TYPICAL HIF1-REGULATED GENES ARE UNALTERED BY OXYGEN IN BOVINE BLASTOCYSTS

2005 ◽  
Vol 17 (2) ◽  
pp. 261
Author(s):  
A. Harvey ◽  
K. Kind ◽  
J. Thompson
Keyword(s):  
Gene Expression ◽  
Oxygen Concentration ◽  
Hypoxia Inducible Factor ◽  
Fold Increase ◽  
Blastocyst Stage ◽  
Bovine Embryo ◽  
Bovine Embryos ◽  
Expression Of Genes ◽  
Regulated Gene Expression

Oxygen-regulated gene expression in the bovine embryo contrasts markedly with that observed in the mouse. Under low (2%) post-compaction oxygen conditions moderate changes in gene expression are observed in the bovine blastocyst (Harvey et al. 2004 Biol. Reprod. 71, in press), compared with 3–4 fold increases in the mouse (Kind et al. 2004 Mol. Reprod. Dev., in press). Specifically, GLUT-1 (Harvey et al. 2004), myotrophin, and anaphase-promoting complex 1 (Harvey et al., unpublished) mRNAs are increased in bovine blastocysts following 2% oxygen culture, compared with those cultured under 20% oxygen. These oxygen-mediated differences in gene expression in the bovine are most likely regulated by hypoxia-inducible factor (HIF)2 transcription factor activity, as we have previously observed that HIF1α protein is not detectable in bovine embryos whereas HIF2α is readily detectable (Harvey et al. 2004). The aim of this study was to determine the effect of post-compaction oxygen concentration on the expression of typically HIF1-regulated and potential HIF2-regulated (suggested from a mouse knockout study; Scortegagna et al. 2003 Nat. Genet. 35, 371) genes in bovine blastocysts. In vitro-produced bovine embryos were generated using standard protocols. Compact morulae were randomly allocated to treatments under 2%, 7%, or 20% oxygen for 72 h from Day 5. Blastocyst RNA was isolated using TriReagent (Molecular Research Center, Inc., Cincinnati, OH, USA) and samples were reverse-transcribed using Superscript II (Invitrogen, Melbourne, Australia). Amplification and analysis of cDNA was achieved by real-time PCR using specific primers and Sybr green PCR master mix (Applied BioSystems, Melbourne, Australia). Statistically significant differences in gene expression were analyzed by ANOVA, P < 0.05. Examination of expression of genes known to be regulated by HIF1 in somatic cells (reviewed by Semenza 2002 Biochem. Pharm. 64, 993) revealed no oxygen-mediated alteration in expression of aldose reductase, cyclooxygenase 2, or inducible nitric oxide synthase. However, the expression of lactate dehydrogenase A (LDHA) displayed a 4-fold increase under 2% oxygen, compared with 7% and 20% oxygen (P < 0.001). Expression of glutathione peroxidase, and CuZn- and Mn-superoxide dismutase (putative HIF2-regulated genes) was not influenced by oxygen concentration post-compaction. This study suggests that typical HIF1-regulated genes are not influenced by alterations in the external oxygen environment in the bovine embryo. These results complement previous observations that HIF1α protein is not detectable in blastocyst-stage bovine embryos, and suggest that LDHA may be an HIF2 target gene in the bovine embryo. As embryo development is influenced by oxygen concentration, levels of LDHA at the blastocyst stage may be used as a marker of oxygen responsiveness.

Effect of oxygen concentration and free radicals on in vitro development of in vitro-produced bovine embryos.

1997 ◽  
Vol 75 (2) ◽  
pp. 483 ◽  
Author(s):  
Y Fujitani ◽  
K Kasai ◽  
S Ohtani ◽  
K Nishimura ◽  
M Yamada ◽  
...  
Keyword(s):  
Free Radicals ◽  
Oxygen Concentration ◽  
Bovine Embryos ◽  
In Vitro Development ◽  
Effect Of Oxygen ◽  
Vitro Development

Effects of oxygen concentrations on developmental competence and transcriptomic profile of yak oocytes

Zygote ◽  
2020 ◽  
Vol 28 (6) ◽  
pp. 459-469
Author(s):  
Ruizhe Li ◽  
Yuzhu Luo ◽  
Jingtao Xu ◽  
Yonggang Sun ◽  
Zhijie Ma ◽  
...  
Keyword(s):  
Oxygen Concentration ◽  
Enrichment Analysis ◽  
Oocyte Quality ◽  
Signalling Pathway ◽  
Developmental Competence ◽  
Low Oxygen ◽  
Transcriptomic Profile ◽  
Low Oxygen Concentration ◽  
Oxygen Concentrations

SummaryOxygen concentration influences oocyte quality and subsequent embryo development, but it remains unclear whether oxygen concentrations affect the developmental competence and transcriptomic profile of yak oocytes. In this study, we investigated the effects of different oxygen concentrations (5% versus 20%) on the developmental competence, reactive oxygen species (ROS) levels, glutathione (GSH) content, and transcriptomic profile of yak oocytes. The results showed that a low oxygen concentration significantly increased the maturation rate of yak oocytes (81.2 ± 2.2% vs 75.9 ± 1.3%) and the blastocyst quality of yak in vitro fertilized embryos. Analysis of ROS and GSH showed that a low oxygen concentration reduced ROS levels and increased the content of GSH (75.05 ± 7.1 ng/oocyte vs 50.63 ± 5.6 ng/oocyte). Furthermore, transcriptomic analysis identified 120 differentially expressed genes (DEGs) between the two groups of oocytes. Gene enrichment analysis of the DEGs indicated multiple cellular processes, including oxidative phosphorylation, transcription regulation, mitochondrial regulation, oestrogen signalling pathway, HIF-1 signalling pathway, TNF signalling pathway, were involved in the response to oxygen concentration alterations. Taken together, these results indicated that a low oxygen concentration improved the developmental competence of yak oocytes.

Effects of oxygen concentration on the metabolism of

1989 ◽  
Vol 1 (2) ◽  
pp. 99 ◽  
Author(s):  
NK Khurana ◽  
RG Wales
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Concentration ◽  
Glycogen Content ◽  
Carbon Dioxide Production ◽  
Morphological Development ◽  
Low Oxygen ◽  
Beneficial Effects ◽  
Low Oxygen Concentration ◽  
Oxygen Concentrations

The utilization of the acid-soluble glycogen pool in pulse-labelled embryos was significantly enhanced during 24- and 48-h chase culture under low oxygen concentrations of 5, 2.5 and 1%. The lower the oxygen tension the greater was the turnover in the pool. The morphological development of embryos was equally as good at very low oxygen concentrations as when embryos were cultured in 5-20% oxygen. Reduction in oxygen concentration enhanced the oxidative utilization of substrate, as measured by rate of carbon dioxide production. The present study could provide an explanation for the discrepancy in glycogen content between mouse blastocysts developing in utero and in vitro and for the reported beneficial effects of low oxygen concentration during development of embryos in culture.

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