scholarly journals 237EFFECTS OF IN VITRO V. IN VIVO CULTURE ON EXPRESSION OF EMBRYO DERIVED GENE TRANSCRIPTS INVOLVED IN APOPTOSIS IN SINGLE BOVINE EMBRYOS

2004 ◽  
Vol 16 (2) ◽  
pp. 239
Author(s):  
H.M. Knijn ◽  
C. Wrenzycki ◽  
P.L.A.M. Vos ◽  
G.C. van der Weijden ◽  
H. Niemann ◽  
...  
Keyword(s):  
Rna Polymerase Ii ◽  
Relative Abundance ◽  
Molecular Basis ◽  
Culture Medium ◽  
Specific Inhibitor ◽  
Control Group ◽  
Cell Stage ◽  
Gene Transcripts

Earlier studies reported that the level of apoptosis in in vitro-produced bovine blastocysts is higher then in in vivo developed blastocysts (Gjorret et al., 2003: Biol. Reprod, in press). The molecular basis for this difference has not yet been studied. The regulation and execution of apoptosis is dependent on a cascade of events in which many proteins are involved. The aim of the present study was to analyze expression of BAX, a pro-apoptotic, and BCL-XL, a anti-apoptotic member of the BCL-2 family, and heat shock protein (HSP 70.1) transcripts in blastocysts cultured in vitro or in vivo. Furthermore, to verify if these transcripts detected in the blastocysts stages were newly expressed from the embryonic genome, a RNA polymerase II specific inhibitor, α-amanitin, was added to the culture medium from the zygote stage onwards, to block transcription. For the in vitro group, embryos were obtained from abattoir oocytes after IVM/IVF and IVC in SOF medium. For the in vivo group, embryos were collected from normally cyclic cows, superovulated with 3000 IU eCG (Intergonan;; Intervet, Tönisvorst, Germany) at day 7 po by non-surgical uterine flushing. The developmental stage of the embryos was determined with stereomicroscopy, and early blastocysts (eb), blastocysts (b), and expanded blastocysts (xb) were collected and frozen at −80°C. For transcription inhibition experiment, embryos were cultured in vitro as for the in vitro group until the 8- to 16-cell stage at 100h after the start of fertilization, one group with 10mM α-amanitin added to the culture medium (α-amanitin group) and the other group without (control group). A highly sensitive semi-quantitative RT-PCR assay (Wrenzycki et al., 1999) Mol. Reprod. Dev. 53, 8–18) was used to determine the relative levels of gene transcripts in single blastocysts and pooled 8- to 16-cell embryos. The relative abundance was calculated on a per cell basis per embryo. Assays were repeated on average eight times. Data on the relative expression of transcripts in blastocysts were analyzed by Anova followed by multiple pairwise comparisons using the Tukey test. No significant differences in relative abundance between in vitro and in vivo cultured embryos, for any of the developmental stages, were found for the three apoptosis related genes. The molecular basis for the difference in level of apoptosis between in vitro and in vivo cultured blastocysts is not related to the level of expression of BAX, BCL-XL and HSP transcripts but other genes involved in the apoptotic cascade may be responsible for the reported differences. The expression of BCL-XL and HSP 70.1 transcripts in the blastocysts was from embryonic origin as no expression of these transcripts was detected in the 8- to 16-cell stage embryos treated with α-amanitin. The expression of BAX gene transcripts was not affected by α-amanitin. Probably the maternally derived transcripts are very stable and not yet degraded at the 8- to 16-cell stage. Table 1 Relative abundance (±SEM) of BAX, BCL-XL, and HSP 70.1 transcripts in bovine single in vitro or in vivo-produced eb, b, and xb and in vitro produced pooled 8- to 16-cell stage embryos treated with or without α-amanitin

193 DIFFERENTIAL EFFECTS OF CULTURE ON APOPTOTIC GENE EXPRESSION IN THE PRE-IMPLANTATION CLONED EMBRYOS OF MINIATURE PIG

2007 ◽  
Vol 19 (1) ◽  
pp. 213
Author(s):  
M. R. Park ◽  
I. S. Hwang ◽  
H. J. Moon ◽  
J. H. Shim ◽  
D. H. Kim ◽  
...  
Keyword(s):  
Gene Expression ◽  
Relative Abundance ◽  
Total Concentration ◽  
Control Group ◽  
Specific Cell ◽  
Miniature Pig ◽  
Cell Stage ◽  
Apoptotic Gene ◽  
Early Embryos

Manipulations of early embryos require that the embryos be placed in vitro. The ability to reproduce in vivo conditions in vitro would greatly facilitate studies on the development of early embryos. A variety of different conditions have been described that result in development of pig embryos from the 1-cell stage to the blastocyst stage in vitro. There is a species-specific cell stage at which the early embryo is very sensitive to in vitro conditions, which generally corresponds to the stage at which the embryo begins producing significant amounts of RNA. The present study was conducted to investigate the relative amounts of apoptotic gene expression in miniature pig NT embryos under culture conditions of different osmolarity. Oocytes were cultured in TCM-199 for 40–44 h at 38.5�C under 5% CO2 in air. Miniature pig ear fibroblast cells were cultured to reach confluency, and the culture was continued for an additional 5–6 days. The NaCl group of embryos was cultured in PZM-3 supplemented with 138 mM NaCl in total concentration (280–320 mOsmol) for the first 2 days, and then cultured in PZM-3 (250–270 mOsmol) for a further 4 days. The control group of embryos was cultured in the PZM-3 for the entire period of in vitro culture. Total RNA samples were prepared from 2 blastocysts using the Roche 1st strand cDNA synthesis kit. Bax and Bcl-xl gene expression of blastocysts was analyzed by real-time RT-PCR. Developemntal rates were analyzed by a GLM procedure of SAS (SAS Institute, Inc., Cary, NC, USA). Relative gene expression was compared by Student's t-test. Blastocyst formation rate in the NaCl group was not different from that in the control group (25.4% and 23.2%, respectively), but the apoptosis rate was significantly lower (P < 0.05) in the NaCl group (1.6%) than in the control (7.1%). The relative abundance of Bax mRNA expression was significantly higher (P < 0.05) in the control group (n = 32) than in the NaCl group (n = 33). However, the relative abundance of Bcl-xl mRNA was significantly higher (P < 0.05) in NaCl group. The relative abundance of Bax/Bcl-xl was significantly higher in the control group than in the NaCl group (P < 0.05). These results indicate that the hypertonic culture condition at the early embryonic stage of miniature pig NT embryos could reduce the frequency of apoptosis through regulating Bax and Bcl-xl gene expression.

175 BOVINE EMBRYO DEVELOPMENT AND MRNA EXPRESSION IN BLASTOCYSTS CULTURED IN ISOLATED MOUSE OVIDUCTS MAINTAINED IN SOF OR KSOM

2006 ◽  
Vol 18 (2) ◽  
pp. 195
Author(s):  
D. Rizos ◽  
B. Pintado ◽  
J. de la Fuente ◽  
P. Lonergan ◽  
A. Gutierrez-Adan
Keyword(s):  
Embryo Development ◽  
Relative Abundance ◽  
Culture Medium ◽  
Embryo Quality ◽  
Blastocyst Stage ◽  
Glut 1 ◽  
Gene Transcripts ◽  
Culture Environment ◽  
Chi Square Analysis

It is well known that modification of the post-fertilization culture environment of mammalian pre-attachment embryos can affect blastocyst quality, manifested in terms of morphology, cryotolerance, and relative abundance of certain gene transcripts. Culture of in vitro-produced bovine zygotes in the ewe oviduct leads to the development of blastocysts of a quality similar to those derived totally in vitro (Rizos et al. 2002 Biol. Reprod. 66, 589-595). However, such a system has disadvantages from a practical and animal welfare point of view. The isolated mouse oviduct (IMO) culture system is a potential alternative and has been successfully used in the in vitro culture of mouse, rat, hamster, and pig embryos from the one-cell stage to the morula/blastocyst stage. The aim of this study was to examine (1) the development of bovine zygotes in the IMO maintained in two different media (SOF and KSOM) in organ culture, and (2) the quality of the resultant blastocysts assessed in terms of the relative abundance of transcripts for several genes that have been previously implicated in embryo quality. Mouse oviducts were isolated from adult Swiss females (CD1, Harlan) the day after mating with an intact male. Approximately 10-15 presumptive bovine zygotes, produced by in vitro oocyte maturation and fertilization, were transferred to the ampullae of the isolated oviducts and were cultured in Transwell plates (Costar, Corning, NY, USA) over 1.1 mL of culture medium (SOF, n = 241 or KSOM, n = 320) at 39�C in an atmosphere of 5% CO2 in air at maximum humidity. A control group of embryos was cultured in droplets (25 �L) of the same culture medium and conditions in parallel (SOF, n = 278, KSOM, n = 225). Five replicates (=days of bovine ovary collection) were carried out. Following 6 days of culture, embryos were recovered from the oviducts/culture drops and blastocysts were snap-frozen in liquid nitrogen. Quantification of all gene transcripts was carried out by real time quantitative RT-PCR. Data on embryo development were analyzed by chi-square analysis and differences in transcript abundance by ANOVA. Culture in the IMO did not affect the proportion of zygotes developing to the blastocyst stage compared to the respective control droplets (SOF: 21.0 vs. 21.9%; KSOM: 22.0 vs. 22.2%). Culture in the IMO in SOF resulted in an increase (P d 0.05) in the abundance of transcripts for Oct-4 and SOX and reduced abundance of Glut-1, Na/K transporter, Cx43, and survivin, compared to control embryos. In contrast, culture in the IMO in KSOM resulted in increased abundance of transcripts for Glut-1, Cx43, Oct-4, and survivin and a reduced expression of Na/K transporter and SOX. Transcripts for G6PDH, IFN, and E-Cad were unaffected by culture environment. In conclusion, culture in the IMO leads to alterations in the relative abundance of transcripts that have been previously associated with embryo quality following culture in the ewe oviduct. However, the effect is dependent on the basal medium used.

180 IDENTIFICATION AND QUANTIFICATION OF DIFFERENTIALLY REPRESENTED TRANSCRIPTS IN PREIMPLANTATION BOVINE EMBRYOS

2008 ◽  
Vol 20 (1) ◽  
pp. 169 ◽  
Author(s):  
C. E. McHughes ◽  
G. K. Springer ◽  
L. D. Spate ◽  
R. Li ◽  
R. J. Woods ◽  
...  
Keyword(s):  
Relative Abundance ◽  
Nuclear Transfer ◽  
Developmental Stages ◽  
Reproductive Technologies ◽  
Blastocyst Stage ◽  
Preimplantation Embryos ◽  
Cell Stage ◽  
Production Techniques

Identification of transcripts that are present at key development stages of preimplantation embryos is critical for a better understanding of early embryogenesis. To that end, this project had two goals. The first was to characterize the relative abundance of multiple transcripts during several developmental stages, including metaphase II-stage oocytes (MPII), and 2-cell-stage (2-cell), precompact morula (PCM), and in vitro-produced blastocyst-stage (IVTBL) embryos. The second was to characterize differences in the relative abundance of transcripts present in in vivo- (IVVBL), in vitro-, and nuclear transfer-produced (NTBL) blastocysts. It was our hypothesis that the identification of differentially represented transcripts from these stages would reveal not only developmentally important genes, but also genes that might be aberrantly expressed due to embryo production techniques. Individual clusters from a large bovine EST project (http://genome.rnet.missouri.edu/Bovine/), which focused on female reproductive tissues and embryos, were compared using Fisher's exact test weighted by number of transcripts per tissue by gene (SAS PROC FREQ; SAS Institute, Inc., Cary, NC, USA). Of the 3144 transcripts that were present during embryogenesis, 125 were found to be differentially represented (P < 0.01) in at least one pairwise comparison (Table 1). Some transcripts found to increase in representation from the MPII to the 2-cell stage include protein kinases, PRKACA and CKS1, as well as the metabolism-related gene, PTTG1. These same transcripts were also found to decrease in representation from the 2-cell to the PCM stage. RPL15 (translation) and FTH1 (immune function) were both more highly represented in the PCM than in the 2-cell stage. From PCM to IVTBL, we saw an increase in RPS11, another translation-related transcript. When comparing blastocyst-stage embryos from different production techniques, several transcripts involved in energy production (e.g., COX7B and COX8A) were found to be more highly represented in the NTBL than in the IVTBL. COX8A was also more highly represented in the IVVBL than in the IVTBL. By investigating these differentially represented transcripts, we will be able to better understand the developmental implications of embryo manipulation. We may also be able to better develop reproductive technologies that lead to in vitro- and nuclear transfer-derived embryos which more closely follow a normal program of development. Table 1. Differentially represented transcripts between developmental stages

71 EFFECT OF CELL QUANTITY IN MICE CHIMERA PRODUCTION BY DEMI-BLASTOCYST AGGREGATION

2012 ◽  
Vol 24 (1) ◽  
pp. 148
Author(s):  
C. Pontes Godoi ◽  
P. D. Moço ◽  
B. Cazari ◽  
P. T. Mihara ◽  
P. V. Silva ◽  
...  
Keyword(s):  
Cell Mass ◽  
Farm Animals ◽  
Control Group ◽  
Chi Square ◽  
Cell Stage ◽  
Exact Test ◽  
Chi Square Test ◽  
Aggregation Technique

Eight-cell-stage to pre-compaction morula are the most used embryonic stages to aggregation, because the embryos, in these early stages, synthesise cell adhesion molecules that increase the aggregation chances among them (Vestweber et al. 1987 Develop. Biol. 124, 451–456). Although post-compaction embryos produce reduced aggregation rates, they are not refractory to this process (Nogueira et al. 2010 Transgenic Res. 19, 344–345). Based on the evidence of less permissive aggregation in post-compaction-stage embryos and the need to expose the inner surface of those embryos to improve aggregation rate, the aim of this study was to evaluate, in mice, the influence of cell quantity (i.e. the quantity of half-embryos put together to aggregate themselves) in the chimerism rate of split blastocysts. Embryos, with preferentially different phenotypes, were obtained from C57BL/6/EGFP and Swiss Webster strains. Females ranging from 21 to 45 days old were superstimulated and mated according to Mancini et al. (2008 Transgenic Res. 17, 1015). Eight-cell-stage embryos (8C) and pre-compaction morula (PCM) were recovered (2 to 2.5 days post coitum) and had their zona pellucida removed using pronase treatment (2 mg mL–1 for 15 min), whereas blastocysts (recovered 3.5 dpc) were split with a microblade controlled by micromanipulator in an inverted microscope (NK2; Eppendorf, Hamburg, Germany and Eclipse Ti; Nikon, Tokyo, Japan, respectively). The aggregation groups were a control (C) with 2 pre-compaction whole embryos (8C or PCM, or both) and 2 experimental with post-compaction embryos [i.e. 2 (2DB) or 4 (4DB) demi-blastocysts]. The structures (2 or 4) of the groups were stuck to each other with the use of phytohemagglutinin (1 mg mL–1) and cultured in vitro by 24 h (37°C, 5% CO2 and saturated humidity). After culture, the presence of chimeric embryos was verified by detection of a single, cohesive cell mass or a structure in an 8 shape with more than one-half of its total diameter aggregated. For the 4DB group, a successful aggregation was considered when, at least 2 of 4 DB had aggregated. The results were analysed using chi-square test, Fisher's exact test and Kruskal-Wallis (to compare among groups, between groups and among medians of group replicates, respectively) and significance was considered when P < 0.05. The aggregation rates for the groups C, 2DB and 4DB were, respectively, 77.3a; 8.3b and 36.4%c (P < 0.001). The increasing of the aggregation technique efficacy, in post-compaction stages, would be particularly interesting in farm animals (e.g. bovine species), where it is not feasible to obtain, in vivo, pre-compaction stages embryos (as 8 cells) and when only trophectoderm aggregation is wanted. It was concluded that cell increasing (from 2 to 4 DB) improved the chimerism rate, but not enough to be similar to the control group. Supported by FAPESP of Brazil.

scholarly journals Plasmodium circumsporozoite protein enhances the efficacy of gefitinib in lung adenocarcinoma cells by inhibiting autophagy via proteasomal degradation of LC3B

2021 ◽  
Author(s):  
Xiao Lu ◽  
Jiao Zhang ◽  
Quanxing Liu ◽  
Dong Zhou ◽  
Xufeng Deng ◽  
...  
Keyword(s):  
Lung Adenocarcinoma ◽  
Cell Viability ◽  
Nude Mice ◽  
Specific Inhibitor ◽  
Proteasomal Degradation ◽  
Circumsporozoite Protein ◽  
Control Group ◽  
Egfr Tkis

Abstract Background: Almost all patients with lung adenocarcinoma (LUAD) develop resistance to EGFR-TKIs, which limit the long-term clinical application of these agents. Accumulating evidence shows one of the main reasons for resistance to EGFR-TKIs is induction of autophagy in tumor cells. Our previous study found that circumsporozoite protein (CSP) in Plasmodium can suppress autophagy in host hepatocytes. However, it is unknown whether CSP-mediated inhibition of autophagy could improve the anti-tumor effect of EGFR-TKIs. Methods: We constructed A549 and H1975 cell lines with stable overexpression of CSP (OE-CSP cells). CCK-8, LDH, flow cytometry, and colony analysis were performed to observe the effect of CSP overexpression on cell viability, the apoptosis rate, and stemness. The sensitizing effect of CSP on gefitinib was evaluated in vivo using a subcutaneous tumor model in nude mice and immunohistochemical assay. The role of CSP in regulation of autophagy was investigated by laser confocal microscopy assay and Western blotting. A transcriptome sequencing assay and real-time polymerase chain reaction were used to determine the levels of mRNA for autophagy-related proteins. Cyclohexane, MG132, TAK-243, and immunoprecipitation assays were used to detect and confirm proteasomal degradation of LC3B. Results: OE-CSP A549 and H1975 cells were more sensitive to gefitinib, demonstrating significant amounts of apoptosis and decreased viability. In the OE-CSP group, autophagy was significantly inhibited, and there was a decrease in LC3B protein after exposure to gefitinib. Cell viability and stemness were recovered when OE-CSP cells were exposed to rapamycin. In nude mice with xenografts of LUAD cells, inhibition of autophagy by CSP resulted in suppression of cell growth and more marked apoptosis during exposure to gefitinib. CSP promoted ubiquitin-proteasome degradation of LC3B, leading to inhibition of autophagy in LUAD cells after treatment with gefitinib . When LUAD cells were treated with the ubiquitin-specific inhibitor TAK-243, cell viability, apoptosis, and growth were comparable between the OE-CSP group and a control group both in vivo and in vitro . Conclusions: CSP can inhibit gefitinib-induced autophagy via proteasomal degradation of LC3B, which suggests that CSP could be used as an autophagy inhibitor to sensitize EGFR-TKIs.

scholarly journals 183 EFFECT OF THE ACIDIC ORGANIC BUFFER MES ON BOVINE IN VITRO EMBRYO PRODUCTION

2005 ◽  
Vol 17 (2) ◽  
pp. 242 ◽  
Author(s):  
K. de Haas ◽  
I. Luther ◽  
D. Gerber
Keyword(s):  
Culture Medium ◽  
Foot And Mouth Disease ◽  
Low Ph ◽  
Mouth Disease ◽  
Control Group ◽  
Maximal Volume ◽  
Mouth Disease Virus ◽  
Foot And Mouth

Transferred embryos carry the risk of being vehicles of organisms causing diseases. Currently, the risk of in vitro-produced (IVP) embryos is more difficult to assess than the risk of in vivo-derived embryos, since less research has been published on the former. Foot and mouth disease virus (FMDV) is extremely sensitive to a low pH and is likely to be destroyed if embryos are exposed to a low pH for a short time. 2-(N-Morphalino)-ethanesulfonic acid (MES); an organic buffer with pKa 6.1; Sigma, South Africa, M2933) as been shown to destroy FMDV at a rate of 90% per minute at pH 6 and at a rate of 90% per second at pH 5 (Acharya et al. 1990 Vet. Microbiol. 23, 21–34; Thomson “Foot-and-mouth disease,” in Infectious Diseases of Livestock with Special Reference to Southern Africa, ed. Coetzer JAW, Thomson GR, and Tustin RC, Oxford University Press, Cape Town, 825–852). The aim of this study was to test whether exposing bovine oocytes and IVP zygotes to the organic buffer MES, buffered at pH 5.5, is detrimental to the development of bovine IVP embryos. IVM, IVF, and IVC was carried out with 1367 oocytes as described earlier [Jooste et al. 2003 Theriogenology 59, 443]. Oocytes were divided into three groups: 484 were used as controls (no MES exposure); 437 were in a maximal exposure group (MAX), i.e. MES treatment after washing of oocytes, after IVM and after IVF, and 446 had a minimal exposure (MIN), i.e. MES treatment after IVF only. To treat the oocytes with MES, 100 oocytes (from ten droplets) were drawn into a pipette in a maximal volume of 100 μL, and placed in 3 mL of MES, swirled around for 10 s, drawn up again in a maximal volume of 100 μL, and placed in 3 mL of culture medium. Oocytes or zygotes were then washed five times in culture medium before being processed through IVM, IVF, or IVC depending on their stage. Exposure of oocytes to MES varied from 30 to 60 s (10 s swirling and a variable time thereafter to pick up). A chi-square test was used to test for differences in cleavage and Day 7 blastocyst yield between control and treatment groups (P < 0.05). Cleavage (70%; 340/484) and blastocyst yield (32%; 156/484) in the control group were not different from those in MIN (68%; 304/446, and 29%; 131/446, respectively), but were significantly higher than for MAX (57%; 249/437, and 18%; 79/437, respectively). In MAX the MES had a harsh effect on the cumulus cells, making them granular and clumpy in appearance. Oocytes treated in MES solution adhered to the bottom of the dish, which made their handling difficult. Exposure time in MES was therefore variable and longer than initially planned. It is concluded that bovine IVP embryos can be exposed to MES without detrimental effect. Treatment with MAX still resulted in blastocysts but it did not yield good numbers. In future trials, treated dishes should be used to prevent oocyte and zygote adherence. Further research is needed to test whether FMDV can be removed from bovine IVP embryos with the described method.

Alteration of extracellular cation concentrations and ratios in culture medium does not affect first cleavage division of hamster zygotes in vitro nor overcome the 'two-cell block'

1989 ◽  
Vol 1 (3) ◽  
pp. 231 ◽  
Author(s):  
BD Bavister ◽  
M Golden
Keyword(s):  
Culture Medium ◽  
Culture Media ◽  
Cell Block ◽  
Cleavage Division ◽  
Cell Stage ◽  
Wide Range ◽  
Standard Culture ◽  
Simple Medium

In vivo fertilized hamster one-cell eggs (embryos) were cultured in a simple medium that was modified to provide a wide range of concentrations and ratios of the four major cation components (sodium, potassium, calcium and magnesium) while maintaining total osmotic pressure at 290 +/- 5 mosm. Embryos were cultured in these media to find the optimum cation concentrations for supporting the first cleavage division in vitro and to determine if physiologically abnormal cation concentrations and/or ratios in standard culture media could account for the 'two-cell block' to development in vitro in this species. Despite using a broad range of ratios for sodium:potassium (from 45:1 to 5:1) and for calcium:magnesium (from 17:1 to 1:1), there were no significant differences in the proportions of fertilized eggs that underwent the first cleavage division (approx. 60-80% across all treatments), and none of the two-cell embryos underwent further cleavage during extended culture. These data demonstrate that the first cleavage division of hamster embryos in vitro is insensitive to extracellular concentrations and ratios of the major cations, and that the non-physiological concentrations and/or ratios of these cations in the culture medium are not the primary reason for the failure of hamster zygotes to develop past the two-cell stage in vitro.

scholarly journals 245RELATIVE ABUNDANCE OF HSP 70 MRNA IN BOVINE EMBRYOS PRODUCED IN VITRO USING DIFFERENT EMBRYO/VOLUME RATIOS IN CULTURE

2004 ◽  
Vol 16 (2) ◽  
pp. 243
Author(s):  
A.T.D. Oliveira ◽  
C. Gebert ◽  
R.F.F. Lopes ◽  
H. Niemann ◽  
J.L. Rodrigues
Keyword(s):  
Relative Abundance ◽  
Blastocyst Stage ◽  
Culture Conditions ◽  
Hatching Rate ◽  
Bovine Embryos ◽  
Blastocyst Formation ◽  
Cleavage Rate ◽  
Gene Transcripts

In spite of in vitro embryo production systems having been greatly improved over recent years, employing a variety of culture conditions (media, protein sources, gas atmosphere, etc.), we still do not know much about the real necessity of embryos to develop under the same conditions as occur in vivo. These differences between in vivo and in vitro culture at preimplantation embryonic stages can produce deviations in gene expression and in normal fetal development (large offspring syndrome). Heat shock proteins (Hsp) are engaged in cell response to regulatory signals or perturbations in the microenviroment and can be used as a sensitive indicator of stress caused by suboptimal culture conditions (Wrenzycki et al., 2001Hum. Reprod. 16, 893–901). Hsp act as chaperones in facilitating protein folding and assembly and stabilize damaged proteins to prevent aggregation of fragments, thereby allowing repair or degradation. The aim of the present study was to investigate the effects of different embryo/volume ratios on bovine embryo development and the relative abundance of Hsp 70.1 gene transcripts. In this experiment, oocytes were isolated from slaugterhouse ovaries and matured, fertilized and cultured in groups of 5, 10, 20 or 30 per each drop of 100μL. The oocytes were matured in TCM 199 supplemented with 0.4% BSA. After maturation, oocytes were fertilized in TALP medium, using frozen/thawed sperm, selected using a percoll density gradient. The zygotes were cultured to the morula or Day 7 blastocyst stage employing SOF supplemented with 0.4 % BSA. Developmental check points were cleavage rate (Day 3pi), blastocyst formation (Day 8pi) and hatching (Day 11pi). A semi-quantitative RT-PCR assay was used to determine the relative levels of gene transcripts in single embryos at morula (Day 6) and blastocyst (Day 7) stages (Wrenzycki et al., 2001 Biol. Reprod. 65, 309–317). Data of cleavage, blastocyst formation and hatching rates were analyzed using chi-square test. Relative abundance (RA) of Hsp 70.1mRNA were compared in tested groups using ANOVA followed a Tukey test. Differences at P&lt;0.05 were considered significant. Results show that no significative difference in hatching rate per blastocyst produced was detected among the four groups. Cleavage rate and blastocyst formation were significantly higher in groups with 5, 10 and 20 embryos compared with drops containing 30 embryos. Hsp transcripts were detected in morula and blastocyst stages in all groups. In morula stage, no differences were observed in the RA of Hsp 70.1mRNA among groups with 5, 10, 20 and 30 embryos cultured per drop. However, in blastocyst stage, the RA was significantly increased in the group with 20 embryos per drop as compared to the group with 5 embryos. The results show that different embryo/volume ratios in culture influence not only cleavage rate, blastocyst formation and hatching rate, but also expression of Hsp 70.1 gene. Further studies changing other culture conditions and using in vivo-derived bovine embryos will aid in elucidating which culture systems are ideal to produce bovine embryos in vitro. This research was supported by CAPES/DAAD program and CNPq.

scholarly journals 243TEMPORAL DIVERGENCE IN THE PATTERN OF MRNA EXPRESSION IN BOVINE EMBRYOS CULTURED FROM THE ZYGOTE TO BLASTOCYST STAGE IN VITRO OR IN VIVO

2004 ◽  
Vol 16 (2) ◽  
pp. 242
Author(s):  
P. Lonergan ◽  
D. Rizos ◽  
A. Gutierrez-Adan ◽  
P.M. Moreira ◽  
B. Pintado ◽  
...  
Keyword(s):  
Growth Factor ◽  
Relative Abundance ◽  
Transcript Abundance ◽  
Blastocyst Stage ◽  
Insulin Like Growth Factor ◽  
Bovine Embryos ◽  
Interferon Tau ◽  
Cell Stage

The objective of this study was to examine the time during the post-fertilization culture period that gene expression patterns of in vitro cultured bovine embryos diverge from those of their in vivo cultured counterparts. Presumptive bovine zygotes were produced by IVM/IVF of immature oocytes collected from the ovaries of slaughtered animals. At approximately 20h post-insemination (hpi), presumptive zygotes were randomly divided into two culture groups, either in vitro in synthetic oviduct fluid or in vivo, and transferred into the ewe oviduct. Embryos were recovered from both systems at approximately 30hpi (2-cell), two (4-cell), three (8-cell), four (16-cell), five (early morula), six (compact morula) or seven (blastocyst) days pi and snap-frozen for the analysis of transcript abundance using real-time PCR. The transcripts studied were interferon-tau, apoptosis regulator box-a (Bax), connexin 43, sarcosine oxidase, glucose transporter 5, mitochondrial Mn-superoxide dismutase, insulin-like growth factor II, and insulin-like growth factor-I receptor, most of which are known from our previous work to be differentially transcribed in blastocysts derived from culture in vitro or in vivo. Analysis was done on pools of 10 embryos. Data were analyzed using one-way repeated measures ANOVA. The relative abundance of the transcripts studied varied throughout the preimplantation period and was strongly influenced by the culture environment. For example, transcripts for interferon-tau were detected from the 8-cell stage onwards in in vitro-cultured embryos but not until the early morula stage in those cultured in vivo. Levels of this transcript increased significantly at the compact morula and blastocyst stages in both groups but were significantly higher (P&lt;0.05) in in vitro-cultured embryos at both stages. mRNA for Bax was not detected before the 8-cell stage in in vitro cultured embryos and not until the 16-cell stage in in vivo cultured embryos. The abundance of this transcript increased significantly thereafter up to the blastocyst stage in both groups. The level of expression was significantly higher (P&lt;0.05) at all stages of development in in vitro-cultured embryos than those cultured in vivo. The relative abundance of Cx43 transcripts decreased in both in vitro- and in vivo-cultured embryos at the 8- to 16-cell stage. Levels remained low thereafter in the in vitro-cultured embryos but significantly increased in those cultured in vivo. Transcript abundance was significantly higher in in vivo cultured embryos from Day 4 onwards with a ten-fold difference presence at the blastocyst stage. Differences also existed for the other transcripts studied. These data demonstrate that changes in transcript abundance in blastocyst stage embryos are in many cases a consequence of perturbed transcription earlier in development. Depending on the transcript, these differences may be evident in as short as 10h of culture.

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