scholarly journals 139PROSTAGLANDIN F2± COMPROMISES DEVELOPMENT OF PRE-IMPLANTATION BOVINE EMBRYOS DURING COMPACTION

2004 ◽  
Vol 16 (2) ◽  
pp. 191 ◽  
Author(s):  
F.N. Scenna ◽  
J.L. Edwards ◽  
F.N. Schrick

Several studies have implicated prostaglandin F2α (PGF) as a major embryotoxic factor during early embryonic development in cattle. Elevated uterine concentrations of PGF were negatively associated with embryo development, quality and pregnancy rates (Schrick FN et al. 1993 Biol. Reprod. 49, 617–621; Hockett ME et al. 1998 J. Anim. Sci. 76 (Suppl 1), 241 abst; Seals RC et al. 1998 Prostaglandins 56, 377–389). Moreover, addition of PGF to culture medium decreased hatching rates of compacted morulae (Scenna FN et al. 2002 Theriogenology 53, 512 abst) and decreased development of pre-compacted (16–32 cell) bovine embryos to blastocyst stage (Scenna FN et al. 2003 Theriogenology 59, 335 abst). Furthermore, administration of an inhibitor of PGF synthesis at the time of embryo transfer improved pregnancy rates in cattle (Schrick FN et al. 2001 Theriogenology 55, 370 abst). The objective of the current study was to identify the period of time during early embryonic development that is most susceptible to the deleterious effects of PGF. After in vitro maturation and fertilization of bovine oocytes, putative zygotes were cultured in KSOMaa plus 0.3% BSA. On Day 4 post-insemination, pre-compacted (16–32 cell) embryos were removed from culture, evaluated for quality, and randomly assigned to one of the following treatments: 1) Control (KSOMaa plus 0.3% polyvinyl alcohol (KSOM-PVA; n=470) or 2) PGF-1 (1ngmL−1 PGF in KSOM-PVA; n=473; Scenna FN et al. 2003 Theriogenology 59, 335 abst). After 48h of incubation in assigned treatments, assessment of development to compacted morula stage was determined. Thereafter, embryos were kept separate according to treatments, sorted by stage of development and quality, and randomly assigned to receive either Control (CON) or PGF-1 supplemented medium until assessment of blastocyst development on Day 9. This random sorting resulted in the formation of four treatment groups comprising the initial treatments and assigned treatments during Days 6–9 (CON-CON, n=366; PGF-CON, n=226; CON-PGF, n=149; PGF-PGF, n=287). Analyses were performed incorporating a randomized incomplete block design using mixed models of SAS (2000) to determine effects of PGF on Days 4–6, 6–9 and 4–9 of development. Data were also analyzed using chi-square. Addition of 1ngmL−1 of PGF to culture medium on Days 4–9 decreased the percentage of pre-compacted embryos reaching blastocyst stage (CON-CON, 47.8%; PGF-PGF, 36%; P<0.05). Moreover, addition of 1ngmL−1 of PGF to the culture medium of pre-compacted bovine embryos on Days 4–6 of development decreased the percentage of compacted morulae on Day 6 (Control, 68.1%; PGF-1, 60.5%; P=0.01). However, the percentage of embryos developing to blastocyst was not decreased following addition of 1ngmL−1 of PGF on Days 6–9 of development (CON-CON, 47.8%; CON-PGF, 42.6%; P>0.05). Results suggest that morula stage embryos during compaction are most susceptible to deleterious effects of PGF.

2020 ◽  
Vol 98 (11) ◽  
Author(s):  
Peter J Hansen

Abstract Typically, bovine embryos are transferred into recipient females about day 7 after estrus or anticipated ovulation, when the embryo has reached the blastocyst stage of development. All the biological and technical causes for failure of a female to produce a blastocyst 7 d after natural or artificial insemination (AI) are avoided when a blastocyst-stage embryo is transferred into the female. It is reasonable to expect, therefore, that pregnancy success would be higher for embryo transfer (ET) recipients than for inseminated females. This expectation is not usually met unless the recipient is exposed to heat stress or is classified as a repeat-breeder female. Rather, pregnancy success is generally similar for ET and AI. The implication is that either one or more of the technical aspects of ET have not yet been optimized or that underlying female fertility that causes an embryo to die before day 7 also causes it to die later in pregnancy. Improvements in pregnancy success after ET will depend upon making a better embryo, improving uterine receptivity, and forging new tools for production and transfer of embryos. Key to accelerating progress in improving pregnancy rates will be the identification of phenotypes or phenomes that allow the prediction of embryo competence for survival and maternal capacity to support embryonic development.


2005 ◽  
Vol 17 (2) ◽  
pp. 216
Author(s):  
P. Booth ◽  
T. Watson ◽  
H. Leese

Pre-implantation embryos can produce and consume amino acids in a manner dependent upon stage of embryonic development (Partridge and Leese 1996 Reprod. Fert. Dev. 8, 945) that may also be predictive of subsequent viability (Houghton et al. 2002 Hum. Reprod. 17, 999). To examine these relationships in the pig, the appearance or depletion of 18 amino acids from a presumptive near-physiological mixture was determined by HPLC in porcine in vitro-produced embryos from the zygote to the blastocyst stage. Cumulus oocyte complexes derived from slaughterhouse prepubertal pig ovaries were matured for 40 h in modified TCM-199 before being fertilized (Day 0) with frozen thawed semen in tris-based medium. After 6 h, presumptive zygotes were denuded and cultured in groups of 20 in NCSU medium modified to contain a physiological mixture of 18 amino acids including 0.1 mM glutamine (NCSUaa). Groups of 2–10 embryos (dependent on stage) were removed on Day 0 (1 cell), Day 1 (2- and 4-cell), Day 4 (compact morula), and Day 6 (blastocyst) and placed in 4 μL NCSUaa for 24 h. After incubation, the embryos were removed and the medium analyzed by HPLC. Each stage was replicated 3–9 times. Since amino acid profiles of 2- and 4-cell embryos were not different, data were combined. Overall, arginine (1.19 ± 0.33), glutamine (0.78 ± 0.34) and threonine (0.05 ± 0.04) were significantly (P < 0.01) depleted from the medium whereas alanine (0.21 ± 0.1), glycine (0.20 ± 0.06), asparagine (0.13 ± 0.5), lysine (0.1 ± 0.03), isoleucine (0.08 ± 0.01), valine (0.05 ± 0.01), leucine (0.04 ± 0.02), phenylalanine (0.03 ± 0.01), and histidine (0.02 ± 0.04) significantly (P < 0.05) accumulated (mean of the 4 sampling timepoints; all values pmol/embryo/h ± SEM). The difference between amino acid accumulation and depletion (balance) was approximately equivalent between Day 0 and the morula stage although turnover (sum of depletion and accumulation) steadily decreased during this period from 3.1 on Day 0 to 1.35 pmol/embryo/h at the morula stage. However, at the blastocyst stage, turnover and balance increased to 6.32 and 2.42 pmol/embryo/h, respectively, i.e. net appearance occurred. Notable changes in amino acid profile during development included decreases in accumulation of asparagine, glutamate, and glycine in the medium and the depletion of glutamine over Days 0, 1, and 4, followed by reversal of these trends by Day 6. These data suggest that pig embryos can alter the accumulation and depletion rates of amino acids in a manner that is dependent on the specific amino acid and the stage of embryonic development. This work was supported by BBSRC.


2019 ◽  
Vol 31 (2) ◽  
pp. 306
Author(s):  
Monika Nõmm ◽  
Rando Porosk ◽  
Pille Pärn ◽  
Kalle Kilk ◽  
Ursel Soomets ◽  
...  

Selecting high-quality embryos for transfer has been a difficult task when producing bovine embryos invitro. The most used non-invasive method is based on visual observation. Molecular characterisation of embryo growth media has been proposed as a complementary method. In this study we demonstrate a culture medium sampling method for identifying potential embryonic viability markers to predict normal or abnormal embryonic development. During single embryo culture, 20µL culture media was removed at Days 2, 5 and 8 after fertilisation from the same droplet (60µL). In all, 58 samples were analysed using liquid chromatography–mass spectrometry. We demonstrate that it is possible to remove samples from the same culture medium droplets and not significantly affect blastocyst rate (25.2%). Changes in any single low molecular weight compound were not predictive enough. Combining multiple low molecular weight signals made it possible to predict Day 2 and 5 embryo development to the blastocyst stage with an accuracy of 64%. Elevated concentrations of lysophosphatidylethanolamines (m/z=453, 566, 588) in the culture media of Day 8 well-developing embryos were observed. Choline (104m/z) and citrate (215m/z) concentrations were increased in embryos in which development was retarded. Metabolic profiling provides possibilities to identify well-developing embryos before transfer, thus improving pregnancy rates and the number of calves born.


2015 ◽  
Vol 27 (1) ◽  
pp. 188
Author(s):  
M. D. Snyder ◽  
J. H. Pryor ◽  
K. J. Veazey ◽  
M. D. Peoples ◽  
G. L. Williamson ◽  
...  

Organization of chromatin structure by the combinatorial patterns of DNA methylation and post-translational histone modification is essential for the establishment and maintenance of proper transcriptional programs that result in the coordination of embryonic development. We previously observed that suppression of transcripts encoding SET domain, bifurcated 1 (SETDB1) using small interfering RNAs (siRNA) is embryonic lethal, with SETDB1-suppressed embryos (n = 361) arresting immediately before the blastocyst stage (blastocyst rate: Control 44.9 ± 4.9% and NULL injected 25.7 ± 6.0%). Studies in rodents indicate SETDB1 is a crucial regulator of transposable elements and that the precise epigenetic regulation of these elements is a key aspect of transcriptional programs controlling pluripotency and placentation. To better characterise the molecular basis of the observed mortality, we analysed expression of the bovine Long Interspersed Nuclear Element 1 family (LINE1) of transposable elements via quantitative real-time reverse-transcription polymerase chain reaction (RT-qPCR). Mature bovine oocytes were obtained from a commercial supplier (De Soto Biosciences, Seymour, TN, USA) and IVF performed by standard laboratory protocol. Eighteen hours after IVF, cumulus cells were removed and presumptive zygotes divided into 3 different treatment groups: non-injected control (CNTL), non-targeting siRNA injected control (siNULL), and zygotes injected with siRNAs targeting SETDB1 (siSETDB1). Each embryo was injected with ~100 pL of siRNAs (10 µM) in fluorescent dextran solution. All zygotes were verified as injected by fluorescent microscopy and then cultured in Bovine Evolve (Zenith Biotech, Guilford, CT, USA) medium supplemented with 4 mg mL of BSA (Probumin, EMD Millipore, Darmstadt, Germany). Groups of embryos (15–20) from each treatment were lysed at the 4-cell, 8-cell, and morula stages, RNA extracted, and analysed by RT-qPCR using GAPDH and YWHAZ as reference genes. A two-way ANOVA and a Student's t-test were used to analyse the results from the RT-qPCR. As expected, siSETDB1-injected morulae displayed dramatic reduction in the level of Setdb1 transcripts as compared to siNULL control (96%; P < 0.05). Preliminary analysis of LINE1 transcripts at the morula stage indicated siSETDB1-injected embryos displayed a 75% reduction compared to the siNULL. Whether alteration in LINE1 regulation contributes to the developmental arrest and embryonic mortality of siSETDB1-injected embryos is under investigation.


2015 ◽  
Vol 27 (1) ◽  
pp. 186
Author(s):  
P. Tribulo ◽  
J. I. Moss ◽  
P. J. Hansen

Wingless-related mouse mammary tumour virus (WNT) signalling participates in early embryonic development to maintain pluripotency, controls cell–cell communication, and modulates cell polarization and migration. To gain an understanding of the regulation of WNT signalling during embryonic development, expression patterns of a variety of molecules involved in WNT signal transduction were evaluated. Specific genes were DKK1, an endogenous inhibitor of canonical WNT signalling, the WNT co-receptors LRP5 and LRP6, WNT-responsive transcription factors, LEF1 and TCF7, and two repressors of WNT-regulated genes, the bovine orthologue of GROUCHO (LOC505120) and AES. Embryos were produced in vitro from oocytes obtained from ovaries collected at a local abattoir. Following oocyte maturation, fertilization was performed with sperm pooled from three randomly selected bulls; a different pool of bulls was used for each replicate. Groups of 30 matured oocytes or embryos at the 2-cell [28–32 h post-insemination (hpi)], 3–4 cell (44–48 hpi), 5–8 cell (50–55 hpi), 9–16 cell (72–75 hpi), morula (120–123 hpi), and blastocyst (168–171 hpi) stages were collected. The zona pellucida was removed with proteinase, RNA was purified, cDNA synthesised using random hexamer primers and real-time qPCR performed. Data analysed were ΔCT values, which were calculated by subtracting the CT value of the geometric mean of the three housekeeping genes (GAPDH, YWHAZ, and SDHA) from the CT value of the sample. The relative transcript abundance was calculated as the 2ΔCT. Data were analysed by least-squares ANOVA using the Proc GLM procedure of SAS (SAS Institute Inc., Cary, NC, USA). A total of 5 replicates were analysed for each developmental stage. Results show significant effects of stage of development for each gene that ranged from P = 0.004 for LRP5 to P ≤ 0.0001 for AES, DKK1, LEF, LOC505120, LRP6, and TCF7. In all cases, expression declined as development advanced. Except for AES, lowest expression occurred at the blastocyst stage. Lowest expression for AES was at the morula stage; expression remained low at the blastocyst stage. For two genes, DKK1 and LEF1, there was no detectable expression at the blastocyst stage. The timing of decline in expression varied between genes, first occurring at the 9–16-cell stage (AES, LEF1, and LOC505120) or morula stage (DKK1, LRP5, LRP6, or TCF7). For DKK1, LEF1, and LRP6, there was also a slight increase in expression from the oocyte to two-cell stage. Results suggest that canonical WNT signalling is reduced at the morula and blastocyst stages relative to earlier stages in development. Research was supported by USDA-NIFA 2011-67015-30688.


2016 ◽  
Vol 28 (2) ◽  
pp. 131
Author(s):  
M. D. Snyder ◽  
J. H. Pryor ◽  
M. D. Peoples ◽  
G. L. Williamson ◽  
M. C. Golding ◽  
...  

Epigenetic patterns established during early bovine embryogenesis via DNA methylation and histone modification patterns are essential for proper gene expression and embryonic development. We have previously discovered that suppression of absent, small, or homeotic-like (ASH2L) with small interfering RNA (siRNA) had no significant effect during in vitro embryo development when compared with its respective control (31.3 ± 2.0% standard error of the mean, n = 466 v. 34.8 ± 1.9%, n = 418). Analysing DNA methylation and histone modifications via immunocytochemistry will further explain the role of ASH2L during embryonic development, specifically at the blastocyst stage. In this experiment, we obtained mature bovine oocytes from a commercial supplier (De Soto Biosciences, Seymour, TN) and preformed IVF following standard laboratory protocol. Eighteen hours after IVF, presumptive zygotes were divided into 3 treatments: noninjected controls, nontargeting siRNA injected controls (siNULL), and injection with siRNA targeting ASH2L (siASH2L). Each embryo was injected with ~100 pL of 20 nM siRNA previously verified to suppress expression of ASH2L by ~79%. Embryos were cultured in Bovine Evolve (Zenith Biotech, Guilford, CT) supplemented with 4 mg mL–1 of BSA (Probumin, Millipore) for 7 days. Blastocysts from each treatment (N = 601) were fixed and prepared for immunocytochemistry following standard laboratory protocol. The following primary antibodies were used to target specific DNA and histone methylation marks: 5mc mAb (Epigentek, Farmingdale, NY), 5hmc pAb, H3K4me3 pAb (Active Motif, Carlsbad, CA), H3K4me2 pAb, H3K9me2–3 mAb, and H3K27me3 mAb (Abcam, Cambridge, MA). Embryos were fluorescently labelled with the following secondary antibodies: Alexa Flour 488 Goat Anti-Rabbit, Alexa 488 Donkey Anti-Goat, and Alexa Flour 594 Goat Anti-Mouse (Invitrogen, Carlsbad, CA). The DNA was stained with Hoechst 33342 (Invitrogen). Fluorescent images were captured using the Zeiss Stallion digital imaging work station. Ratio averages (targeting mark/DNA) were calculated and statistical analysis performed using one-way ANOVA and Tukey’s honestly significant difference to assess treatment effects. The ratio of DNA methylation to total DNA increased in siASH2L as compared with control and siNULL embryos (0.35 ± 0.01, 0.26 ± 0.02, and 0.30 ± 0.01, respectively; P < 0.01). The 5hmC was inversely related to 5mC levels and decreased in siASH2L embryos (0.75 ± 0.01, 0.93 ± 0.02, 0.87 ± 0.02, respectively; P < 0.0001). The H3K4me3 and H3K27me3 are also inversely related with decreased H3K4me3 in siASH2L versus control and siNULL embryos (0.48 ± 0.02, 0.57 ± 0.02, 0.58 ± 0.02, respectively; P < 0.001) and increased H3K27me3 (0.62 ± 0.02, 0.053 ± 0.01, 0.54 ± 0.02, respectively; P < 0.001). No differences were observed in H3K9me2–3 or H3K4me2 labelling across treatments. These results indicate that ASH2L may play a role in DNA methylation by decreasing 5mc and 5hmc conversion, which is a key event during early embryonic development. Suppression of ASH2L also alters global levels of H3H4me3 and H3K27me3, which may lead to transcription aberrations. Further analysis of siASH2L embryos via RNA-seq will help define its role during early embryonic development.


Reproduction ◽  
2012 ◽  
Vol 143 (5) ◽  
pp. 625-636 ◽  
Author(s):  
Chang-Gi Hur ◽  
Eun-Jin Kim ◽  
Seong-Keun Cho ◽  
Young-Woo Cho ◽  
Sook-Young Yoon ◽  
...  

Numerous studies have suggested that K+ channels regulate a wide range of physiological processes in mammalian cells. However, little is known about the specific function of K+ channels in germ cells. In this study, mouse zygotes were cultured in a medium containing K+ channel blockers to identify the functional role of K+ channels in mouse embryonic development. Voltage-dependent K+ channel blockers, such as tetraethylammonium and BaCl2, had no effect on embryonic development to the blastocyst stage, whereas K2P channel blockers, such as quinine, selective serotonin reuptake inhibitors (fluoxetine, paroxetine, and citalopram), gadolinium trichloride, anandamide, ruthenium red, and zinc chloride, significantly decreased blastocyst formation (P<0.05). RT-PCR data showed that members of the K2P channel family, specifically KCNK2, KCNK10, KCNK4, KCNK3, and KCNK9, were expressed in mouse oocytes and embryos. In addition, their mRNA expression levels, except Kcnk3, were up-regulated by above ninefold in morula-stage embryos compared with 2-cell stage embryos (2-cells). Immunocytochemical data showed that KCNK2, KCNK10, KCNK4, KCNK3, and KCNK9 channel proteins were expressed in the membrane of oocytes, 2-cells, and blastocysts. Each siRNA injection targeted at Kcnk2, Kcnk10, Kcnk4, Kcnk3, and Kcnk9 significantly decreased blastocyst formation by ∼38% compared with scrambled siRNA injection (P<0.05). The blockade of K2P channels acidified the intracellular pH and depolarized the membrane potential. These results suggest that K2P channels could improve mouse embryonic development through the modulation of gating by activators.


Reproduction ◽  
2006 ◽  
Vol 132 (2) ◽  
pp. 247-256 ◽  
Author(s):  
Muren Herrid ◽  
Van Ly Nguyen ◽  
Geoff Hinch ◽  
James R McFarlane

There is accumulating evidence that leptin may be directly involved in pre-implantation embryonic development, however, it is unclear whether there is a concentration and stage-dependent regulatory pattern. In this study, the addition of 10 ng/ml human recombinant leptin to the culture medium significantly increased the percentage of two-cell mouse embryos that developed into blastocysts and hatched blastocysts, whereas in the presence of 100 ng/ml leptin, the development rate was significantly inhibited. The total cell numbers in the hatched blastocysts were significantly higher in the presence of 10 ng/ml leptin compared with controls and higher concentrations. The differential sensitivity to leptin was found to vary among embryos at different stages of development. Supplementation of leptin (10 ng/ml) to culture medium at two- to eight-cell stages resulted in a consistent stimulatory effect on embryo development. Most interestingly, the inhibitory effect of high leptin concentration (100 ng/ml) on embryo development was diminished when it was added to the culture medium at the eight-cell stage of development. The concentration-dependent regulation pattern was confirmed using sheep embryos, under similar conditions although sheep embryos appeared to be more sensitive in responding to leptin. Having established the effect of exogenous leptin on embryo development, the expression pattern of leptin and its receptors were also investigated. Leptin mRNA was not detected in mouse two-, four-, eight-cell and blastocyst stage embryos, whereas three isoforms of leptin receptor (Ob-Ra, Ob-Rb and Ob-Re) were identified in these cells, indicating that leptin is likely to modulate embryo development via a paracrine signalling system.


2016 ◽  
Vol 28 (4) ◽  
pp. 482 ◽  
Author(s):  
Qi-En Yang ◽  
Manabu Ozawa ◽  
Kun Zhang ◽  
Sally E. Johnson ◽  
Alan D. Ealy

Protein kinase C (PKC) delta (PRKCD) is a member of the novel PKC subfamily that regulates gene expression in bovine trophoblast cells. Additional functions for PRKCD in early embryonic development in cattle have not been fully explored. The objectives of this study were to describe the expression profile of PRKCD mRNA in bovine embryos and to examine its biological roles during bovine embryo development. Both PRKCD mRNA and protein are present throughout early embryo development and increases in mRNA abundance are evident at morula and blastocyst stages. Phosphorylation patterns are consistent with detection of enzymatically active PRKCD in bovine embryos. Exposure to a pharmacological inhibitor (rottlerin) during early embryonic development prevented development beyond the eight- to 16-cell stage. Treatment at or after the 16-cell stage reduced blastocyst development rates, total blastomere numbers and inner cell mass-to-trophoblast cell ratio. Exposure to the inhibitor also decreased basal interferon tau (IFNT) transcript abundance and abolished fibroblast growth factor-2 induction of IFNT expression. Furthermore, trophoblast adhesion and proliferation was compromised in hatched blastocysts. These observations provide novel insights into PRKCD mRNA expression profiles in bovine embryos and provide evidence for PRKCD-dependent regulation of embryonic development, gene expression and post-hatching events.


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