scholarly journals Increased apoptosis in bovine blastocysts exposed to high levels of IGF1 is not associated with downregulation of the IGF1 receptor

Reproduction ◽  
2011 ◽  
Vol 141 (1) ◽  
pp. 91-103 ◽  
Author(s):  
M A Velazquez ◽  
D Hermann ◽  
W A Kues ◽  
H Niemann
Keyword(s):  
Protein Expression ◽  
Inner Cell Mass ◽  
Polycystic Ovary ◽  
Cell Mass ◽  
Cell Number ◽  
Blastocyst Formation ◽  
Preimplantation Mouse ◽  
High Concentrations ◽  
Igf1 Receptor

The hypothesis that high concentrations of IGF1 can impair embryo development was investigated in a bovine in vitro model to reflect conditions in polycystic ovary syndrome (PCOS) patients. Embryos were either cultured in the absence or presence of a physiological (100 ng/ml) or supraphysiological (1000 ng/ml) IGF1 concentration. Cell allocation, apoptosis, transcript and protein expression of selected genes involved in apoptosis, glucose metabolism and the IGF system were analysed. Supraphysiological IGF1 concentration did not improve blastocyst formation over controls, but induced higher levels of apoptosis, decreased TP53 protein expression in the trophectoderm and increased the number of cells in the inner cell mass (ICM). The increase in ICM cells corresponded with an increase in IGF1 receptor (IGF1R) protein in the ICM. A small, but significant, percentage of blastocysts displayed a hypertrophic ICM, not observed in controls and virtually absent in embryos treated with physiological concentrations of IGF1. Physiological IGF1 concentrations increased total IGF1R protein expression and upregulated IGFBP3 transcripts leading to an increase in blastocyst formation with no effects on cell number or apoptosis. In conclusion, the results support the hypothesis of detrimental effects of supraphysiological IGF1 concentrations on early pregnancy. However, our results do not support the premise that increased apoptosis associated with high levels of IGF1 is mediated via downregulation of the IGF1R as previously found in preimplantation mouse embryos. This in vitro system with the bovine preimplantation embryo reflects critical features of fertility in PCOS patients and could thus serve as a useful model for in-depth mechanistic studies.

Effect of Li+ on preimplantation mouse embryos

Development ◽  
1982 ◽  
Vol 67 (1) ◽  
pp. 51-58
Author(s):  
L. Izquierdo ◽  
M. I. Becker
Keyword(s):  
Inner Cell Mass ◽  
Cell Mass ◽  
Cell Number ◽  
Mouse Embryos ◽  
Preimplantation Mouse Embryos ◽  
Early Embryos ◽  
Preimplantation Mouse

Two-cell mouse embryos were cultured in vitro for different periods in a medium in which NaCl was partially replaced by LiCl at concentrations ranging from 1 to 30 mm. The relative cell number diminished according to increasing LiCl concentrations but the onset of blastulation was not affected, thus resulting in blastulae with fewer cells than normal and with a reduced or absent inner cell mass. Results are discussed in terms of the possible mechanisms involved and are related with the vegetalization induced by Li+ on early embryos of echinoderms and amphibia.

scholarly journals Development of Preimplantation Mouse Embryos in vivo and in vitro

1982 ◽  
Vol 35 (2) ◽  
pp. 187 ◽  
Author(s):  
GM Harlow ◽  
P Quinn
Keyword(s):  
Inner Cell Mass ◽  
Cell Mass ◽  
Cell Number ◽  
Blastocyst Stage ◽  
Culture Conditions ◽  
Cell Stage ◽  
Preimplantation Mouse ◽  
Development In Vitro

The culture conditions for the development in vitro of (C57BL/6 X CBA) F2 hybrid two-cell embryos to the blastocyst stage have been optimized. Commercially available pre-sterile disposable plastic culture dishes supported more reliable development than re-usable washed glass tubes. The presence of an oil layer reduced the variability in development. An average of 85 % of blastocysts developed from hybrid two-cell embryos cultured in drops of Whitten's medium under oil in plastic culture dishes in an atmosphere of 5% O2 : 5% CO2 : 90% N2 ? The time taken for the total cell number to double in embryos developing in vivo was 10 h, and in cultured embryos 17 h. Embryos cultured in vitro from the two-cell stage to blastocyst stage were retarded by 18-24 h in comparison with those remaining in vivo. Day-4 blastocysts in vivo contained 25-70 cells (mean 50) with 7-28 (mean 16) of these in the inner cell mass. Cultured blastocysts contained 19-73 cells (mean 44) with 8-34 (mean 19) of these in the inner cell mass. In the uterine environment, inner-cell-mass blastomeres divided at a faster rate than trophectoderm blastomeres and it is suggested that a long cell cycle is associated with terminal differentiation. Although cultured blastocysts and inner cell masses contained the same number of cells as blastocysts and inner cell masses in vivo, the rate of cell division in cultured inner cell masses was markedly reduced.

scholarly journals Insulin increases the cell number of the inner cell mass and stimulates morphological development of mouse blastocysts in vitro

Development ◽  
1990 ◽  
Vol 110 (3) ◽  
pp. 963-967 ◽  
Author(s):  
M.B. Harvey ◽  
P.L. Kaye
Keyword(s):  
Inner Cell Mass ◽  
Cell Mass ◽  
Insulin Receptors ◽  
Cell Number ◽  
Morphological Development ◽  
Cell Stage ◽  
Morphological Studies ◽  
Preimplantation Mouse ◽  
Stimulation Of

Previous studies showed that insulin promotes cell proliferation and morphological development of preimplantation mouse embryos. In this report, the receptor responsible for these actions and the cell populations that are affected were investigated. Insulin's 9% stimulation of blastocyst cell number was entirely due to a 23% increase in ICM cell number with an EC50 of 0.54 pM. This and the similar degrees of stimulation of immunosurgically isolated ICMs by both physiological and supraphysiological insulin concentrations suggest that insulin receptors are present on the ICM and respond to exogenous insulin transcytosed through the TE to promote expansion of the ICM cell numbers. In morphological studies, insulin increased the number of blastocysts and decreased the number of morulae by 10% after 54 h culture from 2-cell embryos with EC50s of about 0.95 pM. The equivalence of these EC50s suggests mediation of insulin's stimulation of blastocyst formation via insulin receptors which are functionally expressed around the time of compaction at the 8-cell stage. These results support our hypothesis that insulin has an important role in the regulation of growth during preimplantation development.

The preimplantation pig embryo: cell number and allocation to trophectoderm and inner cell mass of the blastocyst in vivo and in vitro

Development ◽  
1988 ◽  
Vol 102 (4) ◽  
pp. 793-803 ◽  
Author(s):  
V.E. Papaioannou ◽  
K.M. Ebert
Keyword(s):  
Inner Cell Mass ◽  
Cell Mass ◽  
Staining Technique ◽  
Cell Number ◽  
Total Cell ◽  
Differential Staining ◽  
Morphological Development ◽  
Total Cell Number

Total cell number as well as differential cell numbers representing the inner cell mass (ICM) and trophectoderm were determined by a differential staining technique for preimplantation pig embryos recovered between 5 and 8 days after the onset of oestrus. Total cell number increased rapidly over this time span and significant effects were found between embryos of the same chronological age from different females. Inner cells could be detected in some but not all embryos of 12–16 cells. The proportion of inner cells was low in morulae but increased during differentiation of ICM and trophectoderm in early blastocysts. The proportion of ICM cells then decreased as blastocysts expanded and hatched. Some embryos were cultured in vitro and others were transferred to the oviducts of immature mice as a surrogate in vivo environment and assessed for morphology and cell number after several days. Although total cell number did not reach in vivo levels, morphological development and cell number increase was sustained better in the immature mice than in vitro. The proportion of ICM cells in blastocysts formed in vitro was in the normal range.

The human blastocyst: cell number, death and allocation during late preimplantation development in vitro

Development ◽  
1989 ◽  
Vol 107 (3) ◽  
pp. 597-604 ◽  
Author(s):  
K. Hardy ◽  
A.H. Handyside ◽  
R.M. Winston
Keyword(s):  
Cell Death ◽  
Inner Cell Mass ◽  
Cell Mass ◽  
Cell Number ◽  
Blastocyst Stage ◽  
Human Embryos ◽  
Cell Numbers ◽  
Human Blastocyst ◽  
Development In Vitro

The development of 181 surplus human embryos, including both normally and abnormally fertilized, was observed from day 2 to day 5, 6 or 7 in vitro. 63/149 (42%) normally fertilized embryos reached the blastocyst stage on day 5 or 6. Total, trophectoderm (TE) and inner cell mass (ICM) cell numbers were analyzed by differential labelling of the nuclei with polynucleotide-specific fluorochromes. The TE nuclei were labelled with one fluorochrome during immunosurgical lysis, before fixing the embryo and labelling both sets of nuclei with a second fluorochrome (Handyside and Hunter, 1984, 1986). Newly expanded normally fertilized blastocysts on day 5 had a total of 58.3 +/− 8.1 cells, which increased to 84.4 +/− 5.7 and 125.5 +/− 19 on days 6 and 7, respectively. The numbers of TE cells were similar on days 5 and 6 (37.9 +/− 6.0 and 40.3 +/− 5.0, respectively) and then doubled on day 7 (80.6 +/− 15.2). In contrast, ICM cell numbers doubled between days 5 and 6 (20.4 +/− 4.0 and 41.9 +/− 5.0, respectively) and remained virtually unchanged on day 7 (45.6 +/− 10.2). There was widespread cell death in both the TE and ICM as evidenced by fragmenting nuclei, which increased substantially by day 7. These results are compared with the numbers of cells in morphologically abnormal blastocysts and blastocysts derived from abnormally fertilized embryos. The nuclei of arrested embryos were also examined. The number of TE and ICM cells allocated in normally fertilized blastocysts appears to be similar to the numbers allocated in the mouse. Unlike the mouse, however, the proportion of ICM cells remains higher, despite cell death in both lineages.

Abnormal development of pre-implantation mouse embryos grown in vitro with [3H]thymidine

Development ◽  
1973 ◽  
Vol 29 (3) ◽  
pp. 601-615
Author(s):  
M. H. L. Snow
Keyword(s):  
Specific Activity ◽  
Inner Cell Mass ◽  
Cell Damage ◽  
Cell Mass ◽  
Cell Number ◽  
Mouse Embryos ◽  
Abnormal Development ◽  
Tritium Concentration ◽  
Cell Stage

Mouse embryos were grown in vitro from the 2-cell stage to blastocysts in the presence of [3H]thymidine. Methyl-T-thymidine and thymidine-6-T(n) were used and both forms found to be lethal at concentrations above 0·1 μCi/ml. Both forms of [3H]Tdr at concentrations between 0·01 and 0·1 μCi/ml caused a highly significant (P < 0·001) reduction in blastocyst cell number. The reduction in cell number, which was positively correlated with specific activity and tritium concentration, was associated with cell damage typical of radiation damage caused by tritium disintegration. Thymidine-6-T(n) also significantly reduced the number of 2-cell embryos forming blastocysts whereas methyl-T-Tdr did not. This difference in effect is assumed to be caused by contamination of one form of [3H]Tdr with a by-product of the tritiation process. A study of the cleavage stages showed that almost all the reduction in cell numbers could be accounted for by selective cell death occurring at the 16-cell stage. Cells which survive that stage cleave at a normal rate. The cells that are most susceptible to [3H]Tdr damage were found to normally contribute to the inner cell mass. The [3H]Tdr-resistant cells form the trophoblast. It is possible to grow blastocysts in [3H]Tdr such that they contain no inner cell mass but are composed entirely of trophoblast. Comparatively short (12 h) incubation with [3H]Tdr at any stage prior to the 16-cell stage will cause this damage. Possible reasons for this differential effect are discussed, and also compared with damage caused by X-irradiation.

scholarly journals Simultaneous gene quantitation of multiple genes in individual bovine nuclear transfer blastocysts

Reproduction ◽  
2007 ◽  
Vol 133 (1) ◽  
pp. 231-242 ◽  
Author(s):  
Craig Smith ◽  
Debbie Berg ◽  
Sue Beaumont ◽  
Neil T Standley ◽  
David N Wells ◽  
...  
Keyword(s):  
Gene Expression ◽  
Nuclear Transfer ◽  
Inner Cell Mass ◽  
Cell Mass ◽  
Ectopic Expression ◽  
Cell Number ◽  
Transcript Levels ◽  
Multiple Genes

During somatic cell nuclear transfer (NT), the transcriptional status of the donor cell has to be reprogrammed to reflect that of an embryo. We analysed the accuracy of this process by comparing transcript levels of four developmentally important genes (Oct4,Otx2,Ifitm3,GATA6), a gene involved in epigenetic regulation (Dnmt3a) and three housekeeping genes (β-actin, β-tubulinandGAPDH) in 21 NT blastocysts with that in genetically half-identicalin vitroproduced (IVP,n=19) andin vivo(n=15) bovine embryos. We have optimised an RNA-isolation and SYBR-green-based real-time RT-PCR procedure allowing the reproducible absolute quantification of multiple genes from a single blastocyst. Our data indicated that transcript levels did not differ significantly between stage and grade-matched zona-free NT and IVP embryos except for Ifitm3/Fragilis, which was expressed at twofold higher levels in NT blastocysts.Ifitm3expression is confined to the inner cell mass at day 7 blastocysts and to the epiblast in day 14 embryos. No ectopic expression in the trophectoderm was seen in NT embryos. Gene expression in NTand IVP embryos increased between two- and threefold for all eight genes from early to late blastocyst stages. This increase exceeded the increase in cell number over this time period indicating an increase in transcript number per cell. Embryo quality (morphological grading) was correlated to cell number for NT and IVP embryos with grade 3 blastocysts containing 30% fewer cells. However, only NT embryos displayed a significant reduction in gene expression (50%) with loss of quality. Variability in gene expression levels was not significantly different in NT, IVP orin vivoembryos but differed among genes, suggesting that the stringency of regulation is intrinsic to a gene and not affected by culture or nuclear transfer.Oct4levels exhibited the lowest variability. Analysing the total variability of all eight genes for individual embryos revealed thatin vivoembryos resembled each other much more than did NT and IVP blastocysts. Furthermore,in vivoembryos, consisting of 1.5-fold more cells, generally contained two- to fourfold more transcripts for the eight genes than did their cultured counterparts. Thus, culture conditions (in vivoversusin vitro) have greater effects on gene expression than does nuclear transfer when minimising genetic heterogeneity.

15 HISTONE ACETYLATION PROFILE OF PORCINE EMBRYOS PRODUCED BY 2 CLONING METHODS WITH OR WITHOUT IN VITRO CULTURE

2016 ◽  
Vol 28 (2) ◽  
pp. 137
Author(s):  
Y. Liu ◽  
A. Lucas-Hahn ◽  
B. Petersen ◽  
R. Li ◽  
D. Hermann ◽  
...  
Keyword(s):  
Gene Expression ◽  
In Vitro Culture ◽  
Histone Acetylation ◽  
Mrna Expression ◽  
Inner Cell Mass ◽  
Cell Mass ◽  
Cell Number ◽  
Cell Numbers ◽  
Cloning Method

Conventional “Dolly”-based cloned (CNT) embryos maintain zona pellucida and can be transferred early in development. Handmade cloned (HMC) embryos are zona free and are cultured to later stages for transfer. We have shown differences between HMC and CNT embryos (Rep. Fert. Dev. 26, 123), and both in vitro culture and cloning method (NT) are associated with alterations in histone acetylation. More studies are needed to clarify whether CNT and HMC embryos differ in epigenetic profiles due to NT method or culture condition. Here we investigated histone acetylation profile of NT embryos produced by CNT or HMC with or without 5 to 6 days in vitro culture, emphasising quality and gene expression in resulting embryos. Both NT methods were performed on Day 0 (D0) with same oocyte batch, donor cells, and culture medium (CNT in group, HMC in well of well). On D0, 5, and 6 after CNT (Clon. Stem Cells 10, 355) or HMC (Zygote 20, 61), all developed embryos of all morphological qualities were collected for immunostaining of H3K18ac, and on D0 and 6 for mRNA expression of the genes KAT2A/2B, EP300, HDAC1/2, DNMT1o/s, and GAPDH. Embryo quality was evaluated normal (clear inner cell mass, high cell number, no fragments) or bad (no clear inner cell mass, low cell number, fragments). Cell numbers per blastocyst were counted on D5 and 6. Differences in cell number and H3K18ac level between different groups and days were analysed by ANOVA; gene expression data were analysed by GLM (SAS version 9.3, SAS Institute Inc., Cary, NC, USA). Embryo development rates of both NT methods were reported previously (Rep. Fert. Dev. 26, 123). On D5 and 6, all HMC embryos were evaluated as normal, but the CNT group contained both normal and bad embryos. Regarding cell numbers (Table 1), on D5 there was no difference between normal CNT and HMC embryos, but numbers were lower in CNT bad embryos. On D6 the blastocyst cell number was lower in both normal and bad CNT embryos compared with HMC. Regarding H3K18ac levels (Table 1), no differences were found on D5 between normal CNT and HMC embryos, but on D6 both CNT normal and bad embryos had higher H3K18ac level compared with HMC. On D0, no difference was found in mRNA expression of all 8 genes. On D6, KAT2A expression was slight increased (1.8-fold) in CNT compared with HMC embryos (P < 0.05). In conclusion, no differences were found between CNT and HMC embryos after completed NT procedure (D0) or after 5 days in vitro culture. However, differences in quality (cell number and H3K18ac) and gene expression between the 2 NT methods were observed when blastocyst expansion was initiated (D6). Thus, the 2 NT methods seem to produce embryos of similar quality, which is maintained over 5 days in vitro culture, but thereafter gene expression and histone acetylation are more active in CNT embryos. Table 1.Cell number and H3K18ac level1

77 Development and quality of in vitro bovine hemi embryos produced by blastomere separation and embryo bisection

2019 ◽  
Vol 31 (1) ◽  
pp. 164
Author(s):  
A. E. Ynsaurralde Rivolta ◽  
M. Suvá ◽  
V. Alberio ◽  
C. Vazquez Echegaray ◽  
A. Guberman ◽  
...  
Keyword(s):  
Inner Cell Mass ◽  
Cell Mass ◽  
Monozygotic Twin ◽  
Cell Number ◽  
Control Group ◽  
Cell Stage ◽  
Exact Test ◽  
Development Rates

Bovine monozygotic production of twins became popular in the 1980s as a technique to multiply high value genetics. Moreover, it also became a powerful model for research. Different techniques have been used on bovine embryos obtained by superovulation. In this work, we compared the development rates and quality of monozygotic twin embryos produced by blastomere separation (BS) and embryo bisection (EB) of IVF embryos. To this aim, cumulus-oocytes complexes collected from slaughterhouse ovaries were in vitro matured in TCM 199 containing 10% fetal bovine serum, 10µg mL−1 FSH, 0.3mM sodium pyruvate, 100mM cysteamine, and 2% antibiotic-antimycotic for 24h, at 6.5% CO2 in humidified air and 38.5°C. The IVF was performed with 16×106 spermatozoa per mL for 5h. Afterward, presumptive zygotes were cultured in SOF medium for 7 days at 38.5°C and 5% O2. After 24h of culture, blastomeres of 2-cell stage embryos (N=114) were separated and each one was cultured individually in a microwell for 7 days. Embryo bisection (N=179) was performed manually on Day-7 blastocysts previously depleted of their zonae pellucidae, under stereoscopic microscope. Hemi embryos were cultured for 24h and then twins and single blastocyst rates were calculated. For quality assessment, diameter, total and inner cell mass (ICM) cell number of hemi embryos (BS: 6 couples; ES: 10 couples) and the control group (C: 11) were evaluated. The ICM cell number was measured by immunofluorescence staining using SOX2 antibody and the percentage of ICM and trophectoderm (TE) cells was calculated. The results were analysed using Fisher’s exact test and ANOVA with mean comparison using Tukey’s test (P=0.05). No statistical differences were found in blastocyst rates of twins and single hemi embryos produced by BS (28 and 25%) or EB (23 and 32%). Blastocyst diameter was similar between groups and control. Hemi embryos exhibited lower total and ICM cell number than control (BS: 43±18, EB: 57±14v. C: 93±35 and BS: 16±7, EB: 12±8v. C: 34±19). However, BS hemi embryos had higher ICM and lower TE percentage (40/60%) compared with the EB group (20/80%). The control group did not differ with hemi embryo treatments for ICM and TE (30/70%). Our preliminary results have indicated that although the development rates of hemi embryos produced in vitro were similar between both techniques, blastomere separation generates better quality embryos than blastocyst bisection.

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