240 DEVELOPMENT, DIFFERENTIATION, AND Trk EXPRESSION IN PARTHENOGENETIC BOVINE BLASTOCYSTS

2008 ◽  
Vol 20 (1) ◽  
pp. 199
Author(s):  
J. N. Caamaño ◽  
M. Muñoz ◽  
M. Álvarez-Viejo ◽  
C. Díez ◽  
C. de Frutos ◽  
...  
Keyword(s):  
Inner Cell Mass ◽  
Cell Mass ◽  
Embryonic Stem ◽  
Neurotrophin Receptor ◽  
Positive Staining ◽  
P75 Neurotrophin Receptor ◽  
Blastocyst Development ◽  
Surface Receptors ◽  
Parthenogenetic Embryos

Parthenogenetic embryos allow study of the roles of paternal and maternal genomes in early mammalian development. Nevertheless, pregnancies established with parthenotes arrest around 48 days. Genomic imprinting alterations, fewer cells, and apoptotic index are higher in parthenotes than in IVF embryos and are likely to contribute to the failure to reach full-term development. Neurotrophins are a family of anti-apoptotic cytokines that mediate survival, growth, and differentiation by binding to two types of cell surface receptors, tyrosine kinase (Trk) and the low affinity p75 neurotrophin receptor (p75). Trk and p75 receptors have been localized in early bovine in vitro-produced embryos. At present there are no available data on expression of Trk and numbers of cells in the inner cell mass (ICM) and the trophectoderm (TE) of parthenogenetic embryos. The aim of this study was to evaluate the quality of bovine parthenotes in terms of cell allocation and blastocyst development, and to analyze TrkA, TrkB, and TrKC expression in the ICM and TE. Starting from in vitro-matured slaughterhouse oocytes, embryos were produced by conventional IVF, while parthenotes resulted from ionomycin activation followed by 6-dimethylaminopurine. Zygotes were cultured in SOF + 6 gL– 1 BSA. In vitro development was assessed for IVF embryos on (and referred to on) Days 3, 6, 7, and 8 after fertilization, and 24 h before these time points for parthenotes. Data were analyzed by the GLM procedure of SAS SAS Institute, Inc., Cary, NC, USA). Parthenotes cleaved at rates similar to IVF embryos (80.8 � 3.9 v. 85.8 � 3.9, respectively), but percentages of 5–8 and 8–16 cell stages were lower in parthenotes (40.4 � 4.3 v. 67.9 � 4.3, P < 0.005, and 9.7 � 3.5 v. 25.3 � 3.5, P < 0.01, respectively). However, parthenogenetic blastocyst rates were higher than those in IVF embryos (Day 6: 33.6 � 2.6 v. 11.0 � 2.6, P < 0.005; Day 7: 49.2 � 4.1 v. 30.0 � 4.1, P < 0.02). Double staining showed fewer TE cells in parthenotes (78.7 � 8.5) than in IVF embryos (111.0 � 8.6, P < 0.02). This reduction accounted for a reduced number of total cells in parthenotes (105.3 � 9.9) v. controls (144.0 � 9.8, P < 0.01), while numbers of cells in the ICM were comparable (27.9 � 3.5 v. 31.1 � 3.5, in parthenotes and controls, respectively). As in the case of IVF embryos, immunocytochemical analysis showed positive staining for Trk receptors in parthenotes. Although parthenotes showed blastocyst development rates higher than in IVF embryos, the reduced amount of TE cells in parthenotes could negatively affect implantation. Interestingly, parthenotes do not contain abnormally reduced cell numbers in their ICM, and they express Trks. Therefore, specific stimulation of these receptors with appropriate cytokines could improve blastocyst development and embryonic stem cell derivation. This work was supported by the Spanish Ministry of Science and Education (AGL2005-04479). Dr. Muñoz was supported by FICYT.

scholarly journals ID: 1065 Establishment of parthenogenetic diploid embryonic stem cells in mice

2017 ◽  
Vol 4 (S) ◽  
pp. 147
Author(s):  
Ho Thi-Kim Ngan ◽  
Nguyen Van Thuan ◽  
Hong-Thuy Bui
Keyword(s):  
Stem Cells ◽  
Cell Lines ◽  
Inner Cell Mass ◽  
Cell Mass ◽  
Embryonic Stem ◽  
Cell Number ◽  
Strontium Chloride ◽  
Blastocyst Quality ◽  
Parthenogenetic Embryos

Parthenogenesis is a process in which zygotes are produced without sperm presence. Due to lack of paternal genes, parthenogenetic embryos cannot develop to full-term; however, these embryos show a great potential to generate histocompatible stem cells (parthenogenetic embryonic stem – pES cells) for transplantation. In this research, parthenogenetic activation in the mouse was carried out using strontium chloride (SrCl2) combined with cytochalasin B (CB). The rate of embryo development, blastocyst quality and expression of acetylation of histone H4 lysine 12 (H4K12Ac) were investigated, while parthenogenetic blastocysts were used to establish pES cells. The results showed that rate of in vitro blastulation of parthenogenetic embryos was lower than that of fertilized ones (45.1% vs 98.0%, respectively). In addition, blastocysts developed from parthenogenetic embryos also expressed lower quality, which was demonstrated by lower total cell number. Moreover, H4K12Ac expression significantly decreased in the inner cell mass (ICM) of parthenogenetic blastocysts compared to fertilized ones, indicating a possible reason for lower blastocyst quality. Following embryo collection and activation, two ES cell lines – fertilized (fES) and pES cell lines have been successfully established and maintained long term in vitro. To sum up, differences in blastocyst quality and H4K12Ac expression in ICM cells of blastocyst may contribute to aberrant developmental and embryonic stem cell formation in parthenogenetic embryos.

The responsiveness of embryonic stem cells to alpha and beta interferons provides the basis of an inducible expression system for analysis of developmental control genes

1993 ◽  
Vol 13 (12) ◽  
pp. 7971-7976
Author(s):  
L M Whyatt ◽  
A Düwel ◽  
A G Smith ◽  
P D Rathjen
Keyword(s):  
Gene Expression ◽  
Inner Cell Mass ◽  
Es Cells ◽  
Expression System ◽  
Cell Mass ◽  
Embryonic Stem ◽  
Expression Vectors ◽  
Developmental Control ◽  
Developmental Potential

Embryonic stem (ES) cells, derived from the inner cell mass of the preimplantation mouse embryo, are used increasingly as an experimental tool for the investigation of early mammalian development. The differentiation of these cells in vitro can be used as an assay for factors that regulate early developmental decisions in the embryo, while the effects of altered gene expression during early embryogenesis can be analyzed in chimeric mice generated from modified ES cells. The experimental versatility of ES cells would be significantly increased by the development of systems which allow precise control of heterologous gene expression. In this paper, we report that ES cells are responsive to alpha and beta interferons (IFNs). This property has been exploited for the development of inducible ES cell expression vectors, using the promoter of the human IFN-inducible gene, 6-16. The properties of these vectors have been analyzed in both transiently and stably transfected ES cells. Expression was minimal or absent in unstimulated ES cells, could be stimulated up to 100-fold by treatment of the cells with IFN, and increased in linear fashion with increasing levels of IFN. High levels of induced expression were maintained for extended periods of time in the continuous presence of the inducing signal or following a 12-h pulse with IFN. Treatment of ES cells with IFN did not affect their growth or differentiation in vitro or compromise their developmental potential. This combination of features makes the 6-16-based expression vectors suitable for the functional analysis of developmental control control genes in ES cells.

scholarly journals Cell lineage allocation in equine blastocysts produced in vitro under varying glucose concentrations

Reproduction ◽  
2015 ◽  
Vol 150 (1) ◽  
pp. 31-41 ◽  
Author(s):  
Young-Ho Choi ◽  
Pablo Ross ◽  
Isabel C Velez ◽  
B Macías-García ◽  
Fernando L Riera ◽  
...  
Keyword(s):  
High Glucose ◽  
Culture Medium ◽  
Inner Cell Mass ◽  
Cell Mass ◽  
Cell Lineage ◽  
Primitive Endoderm ◽  
Blastocyst Development ◽  
Embryo Culture Medium ◽  
Effect Of Glucose

Equine embryos developin vitroin the presence of high glucose concentrations, but little is known about their requirements for development. We evaluated the effect of glucose concentrations in medium on blastocyst development after ICSI. In experiment 1, there were no significant differences in rates of blastocyst formation among embryos cultured in our standard medium (DMEM/F-12), which contained >16 mM glucose, and those cultured in a minimal-glucose embryo culture medium (<1 mM; Global medium, GB), with either 0 added glucose for the first 5 days, then 20 mM (0-20) or 20 mM for the entire culture period (20-20). In experiment 2, there were no significant differences in the rates of blastocyst development (31–46%) for embryos cultured in four glucose treatments in GB (0-10, 0-20, 5-10, or 5-20). Blastocysts were evaluated by immunofluorescence for lineage-specific markers. All cells stained positively forPOU5F1. An inner cluster of cells was identified that included presumptive primitive endoderm cells (GATA6-positive) and presumptive epiblast (EPI) cells. The 5-20 treatment resulted in a significantly lower number of presumptive EPI-lineage cells than the 0-20 treatment did.GATA6-positive cells appeared to be allocated to the primitive endoderm independent of the formation of an inner cell mass, as was previously hypothesized for equine embryos. These data demonstrate that equine blastocyst development is not dependent on high glucose concentrations during early culture; rather, environmental glucose may affect cell allocation. They also present the first analysis of cell lineage allocation inin vitro-fertilized equine blastocysts. These findings expand our understanding of the factors that affect embryo development in the horse.

scholarly journals PTPN11 (SHP2) Is Indispensable for Growth Factors and Cytokine Signal Transduction During Bovine Oocyte Maturation and Blastocyst Development

Cells ◽  
2019 ◽  
Vol 8 (10) ◽  
pp. 1272 ◽  
Author(s):  
Muhammad Idrees ◽  
Lianguang Xu ◽  
Seok-Hwan Song ◽  
Myeong-Don Joo ◽  
Kyeong-Lim Lee ◽  
...  
Keyword(s):  
Growth Factors ◽  
Embryo Development ◽  
Oocyte Maturation ◽  
Inner Cell Mass ◽  
Cell Mass ◽  
Specific Inhibitor ◽  
Mrna Translation ◽  
Bovine Oocyte ◽  
Blastocyst Development

This study was aimed to investigate the role of SHP2 (Src-homology-2-containing phosphotyrosine phosphatase) in intricate signaling networks invoked by bovine oocyte to achieve maturation and blastocyst development. PTPN11 (Protein Tyrosine Phosphatase, non-receptor type 11) encoding protein SHP2, a positive transducer of RTKs (Receptor Tyrosine Kinases) and cytokine receptors, can play a significant role in bovine oocyte maturation and embryo development, but this phenomenon has not yet been explored. Here, we used different growth factors, cytokines, selective activator, and a specific inhibitor of SHP2 to ascertain its role in bovine oocyte developmental stages in vitro. We found that SHP2 became activated by growth factors and cytokines treatment and was highly involved in the activation of oocyte maturation and embryo development pathways. Activation of SHP2 triggered MAPK (mitogen-activated protein kinases) and PI3K/AKT (Phosphoinositide 3-kinase/Protein kinase B) signaling cascades, which is not only important for GVBD (germinal vesical breakdown) induction but also for maternal mRNA translation. Inhibition of phosphatase activity of SHP2 with PHPS1 (Phenylhydrazonopyrazolone sulfonate 1) reduced oocytes maturation as well as bovine blastocyst ICM (inner cell mass) volume. Supplementation of LIF (Leukemia Inhibitory Factor) to embryos showed an unconventional direct relation between p-SHP2 and p-STAT3 (Signal transducer and activator of transcription 3) for blastocyst ICM development. Other than growth factors and cytokines, cisplatin was used to activate SHP2. Cisplatin activated SHP2 modulate growth factors effect and combine treatment significantly enhanced quality and rate of developed blastocysts.

scholarly journals 173 EFFECT OF CULTURE SYSTEM FOR IVM-IVF PIG EMBRYOS ON THE ICMS ABILITY TO PRODUCE OUTGROWTHS FOR EMBRYONIC STEM CELL DERIVATION

2005 ◽  
Vol 17 (2) ◽  
pp. 237 ◽  
Author(s):  
G. Lazzari ◽  
I. Lagutina ◽  
G. Crotti ◽  
P. Turini ◽  
S. Colleoni ◽  
...  
Keyword(s):  
Cell Mass ◽  
Embryonic Stem ◽  
Farm Animals ◽  
Es Cell ◽  
Blastocyst Formation ◽  
Blastocyst Development ◽  
In Vivo Culture

Attempts to derive true embryonic stem cells in large farm animals rely on the supply of good quality embryos. In these species, including the pig, pre-implantation-stage embryos can be produced by in vitro techniques from slaughterhouse ovaries. The objective of this study was to evaluate the ability of the inner cell masses (ICMs) of pig embryos, produced in vitro by different methods, to provide viable initial outgrowths of ICM cells that could be subsequently subcultured and expanded. Porcine oocytes were recovered from slaughtered donors and matured in vitro for 40–44 h in DMEM-F12 supplemented with 10% FCS, 0.05 IU LH and FSH (Menogon, Ferring, Milan, Italy), 0.3 mM cystine, 0.5 mM cysteamine, 50 ng/mL long-EGF, 100 ng/mL long-IGF1, 5 ng/mL bFGF (Sigma-Aldrich, Milan, Italy) in 5% CO2 at 38.5°C. Boar frozen-thawed semen was separated on a percoll gradient and diluted in TALP medium with PHE (penicillamine, hypotaurine, epinefrine) to a concentration ranging from 0.05 to 0.1 million sperm per mL. Oocytes were partially decumulated, co-incubated with sperm for 24 h, and finally denuded and cultured in microdrops of mSOFaa or NCSU. After cleavage, approximately half of the cleaved embryos were surgically transferred into the sheep oviduct for 4 days of in vivo culture and the remaining embryos were left in vitro in the two media. On Day +6 in vivo-cultured embryos were recovered from the sheep oviduct. Blastocyst formation and quality were comparatively evaluated in the three culture groups. Quality specifically referred to the morphology/size of the ICM according to the following criteria: ICM A (large/prominent), ICM B (flat), and ICM C (non-visible). All embryos with a visible inner cell mass were subjected to microdissection with needles to recover the ICMs that were then plated on feeder-layers of mitomycin-treated STO fibroblasts. Attachment and outgrowth was evaluated 48–72 h post-plating. Results are presented in Table 1. Our data indicate that in vivo culture of pig embryos in the sheep oviduct greatly enhance both blastocyst development and ICM quality. As a consequence the efficiency of outgrowth formation, following plating for ES cell derivation, was significantly higher with ICMs derived from IVM-IVF pig embryos cultured in vivo as compared to their in vitro-cultured counterparts. Within the two culture media tested for in vitro culture, SOF and NCSU, the rate of blastocyst formation was similar but the quality of SOF-cultured embryos is higher. In conclusion, embryo/ICM quality represents a fundamental requirement for the derivation of ES cell lines, and in vivo culture in the sheep oviduct provides the most efficient source of high quality IVM-IVF pig embryos. Table 1. Blastocyst development and ICM quality of in vitro-produced pig embryos This work was supported by the Istituto Superiore di Sanità, Programma Nazionale Cellule Staminali, Rome, Italy, grant No. CS 11.

Leptin treatment of in vitro cultured embryos increases outgrowth rate of inner cell mass during embryonic stem cell derivation

2019 ◽  
Vol 55 (7) ◽  
pp. 473-481 ◽  
Author(s):  
Ali Cihan Taskin ◽  
Ahmet Kocabay ◽  
Ayyub Ebrahimi ◽  
Sercin Karahuseyinoglu ◽  
Gizem Nur Sahin ◽  
...  
Keyword(s):  
Stem Cell ◽  
Embryonic Stem Cell ◽  
Inner Cell Mass ◽  
Cell Mass ◽  
Embryonic Stem ◽  
Stem Cell Derivation

Derivation of human embryonic stem cell lines after blastocyst microsurgery

2010 ◽  
Vol 88 (3) ◽  
pp. 479-490 ◽  
Author(s):  
Guoliang Meng ◽  
Shiying Liu ◽  
Xiangyun Li ◽  
Roman Krawetz ◽  
Derrick E. Rancourt
Keyword(s):  
Stem Cells ◽  
Embryonic Stem Cells ◽  
Cell Lines ◽  
Clinical Medicine ◽  
Inner Cell Mass ◽  
Cell Mass ◽  
Embryonic Stem ◽  
Hesc Lines

Embryonic stem cells (ESCs) are derived from the inner cell mass (ICM) of the blastocyst. Because of their ability to differentiate into a variety of cell types, human embryonic stem cells (hESCs) provide an unlimited source of cells for clinical medicine and have begun to be used in clinical trials. Presently, although several hundred hESC lines are available in the word, only few have been widely used in basic and applied research. More and more hESC lines with differing genetic backgrounds are required for establishing a bank of hESCs. Here, we report the first Canadian hESC lines to be generated from cryopreserved embryos and we discuss how we navigated through the Canadian regulatory process. The cryopreserved human zygotes used in this study were cultured to the blastocyst stage, and used to isolate ICM via microsurgery. Unlike previous microsurgery methods, which use specialized glass or steel needles, our method conveniently uses syringe needles for the isolation of ICM and subsequent hESC lines. ICM were cultured on MEF feeders in medium containing FBS or serum replacer (SR). Resulting outgrowths were isolated, cut into several cell clumps, and transferred onto fresh feeders. After more than 30 passages, the two hESC lines established using this method exhibited normal morphology, karyotype, and growth rate. Moreover, they stained positively for a variety of pluripotency markers and could be differentiated both in vitro and in vivo. Both cell lines could be maintained under a variety of culture conditions, including xeno-free conditions we have previously described. We suggest that this microsurgical approach may be conducive to deriving xeno-free hESC lines when outgrown on xeno-free human foreskin fibroblast feeders.

183 DEVELOPMENT OF PORCINE EMBRYOS MICROINJECTED WITH PORCINE EMBRYONIC GERM CELLS

2006 ◽  
Vol 18 (2) ◽  
pp. 199
Author(s):  
C.-H. Park ◽  
S.-G. Lee ◽  
D.-H. Choi ◽  
M.-G. Kim ◽  
C. K. Lee
Keyword(s):  
Germ Cells ◽  
Fluorescent Protein ◽  
Inner Cell Mass ◽  
Es Cells ◽  
Cell Mass ◽  
Embryonic Stem ◽  
Green Fluorescent Protein Gene ◽  
Cleavage Stage ◽  
Allocation Pattern

Embryonic germ (EG) cells, derived from primordial germ cells in the developing fetus, are similar to embryonic stem (ES) cells in terms of expression pattern of undifferentiated markers and their ability to colonize both the somatic and the germ cell lines following injection into a host blastocyst, which has been proven in mouse. Several studies using porcine EG cells have shown that it is possible to produce somatic chimeras after blastocyst injection. However, not only was the degree of reported chimerism low, but also there has been no report about the fate of injected EG cells in porcine blastocysts. This study was designed to observe the distribution pattern of porcine EG cells in chimeric blastocyst after injection into cleavage-stage porcine embryos. To ascertain development of microinjected porcine embryos with EG cells, 10 to 15 EG cells were injected into cleavage stage of in vitro fertilized embryos and cultured up to blastocyst. Also, porcine EG cells were labeled with DiO (Invitrogen, Carlsbad, CA) on the cell membrane or transfected with green fluorescent protein gene to observe whether the EG cells injected in the host embryo would incorporate into the inner cell mass (ICM) or trophectoderm (TE). Chimeric embryos were produced and allowed to develop into blastocysts to investigate the injected EG cells would come to lie in ICM and/or TE of the blastocyst, by scoring their position. In result, developmental rate was similar in all treatments. In all treatments, EG cells were mainly allocated in both ICM and TE of the chimeric blastocysts. These results suggest that examining the allocation pattern of injected EG cells, maintained pluripotency in vitro, could provide clues of differentiation process in vivo. Furthermore, to enhance the allocation of EG cells into the embryonic lineage, it would be required to optimize the culture condition for EG cells as well as embryos. Further experiment are needed to determine whether the injected EG cells could maintain their properties throughout the environment in the embryonic development in vitro. Table 1. Distribution of the porcine EG cells microinjected into cleavage-stage embryos

165 EXPRESSION OF Oct-4 IN BUFFALO (BUBALUS BUBALIS) EMBRYOS GENERATED THROUGH IN VITRO FERTILIZATION OR PARTHENOGENETIC ACTIVATION

2008 ◽  
Vol 20 (1) ◽  
pp. 162
Author(s):  
D. Kumar ◽  
T. Anand ◽  
K. P. Singh ◽  
M. S. Chauhan ◽  
P. Palta ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Inner Cell Mass ◽  
Polar Body ◽  
Cell Mass ◽  
Embryonic Stem ◽  
Bubalus Bubalis ◽  
Dnase I ◽  
Parthenogenetic Activation ◽  
Cell Lysate

Octamer-4 (Oct-4) is a member of Class V of the POU transcription factors family, which is involved in transcriptional regulation during early embryonic development and cell differentiation. It is expressed in the inner cell mass of blastocysts and in embryonic stem cells (ESCs), and its expression is widely used as a marker of pluripotency in ESCs in many species. This study was, therefore, carried out to examine the expression of Oct-4 in embryos at the 2-, 4-, 8- to 16-cell, morula, and blastocyst stages generated through IVF or parthenogenetic activation. A total of 100 embryos were used in the study, 10 for each embryonic stage from both methods of embryo production. Immature oocytes obtained from slaughterhouse buffalo (Bubalus bubalis) ovaries were subjected to IVM in TCM-199 + 10% FBS + 5 µg mL–1 pFSH + 0.81 mm sodium pyruvate for 24 h in a CO2 incubator (5% O2, 5% CO2, 90–95% relative humidity) at 38.5�C. IVF was carried out immediately after IVM; the cleaved embryos were cultured for 8 days in CR2 medium containing 0.6% BSA and 10% FBS for production of embryos at different stages. For production of embryos through parthenogenesis, after 24 h of IVM, oocytes were denuded of cumulus cells by incubation in 0.2% hyaluronidase in Dulbecco's phosphate-buffered saline for 2 min. The denuded oocytes with a prominent polar body were parthenogenetically activated by exposure to 7% ethanol for 7 min, followed by incubation with 2 mm 6-dimethyl aminopurine in CR2 medium for 3.5 h in a CO2 incubator (5% O2, 5% CO2, 90–95% relative humidity) at 38.5�C, and then subjected to IVC as described above. A two-step RT-PCR was carried out using Cells-to-cDNA Kit-II (Ambion, Austin, TX, USA), using bovine primers 52-GTT CTC TTT GGA AAG GTG TTC-3' and 5'-ACA CTC GGA CCA CGT CTT TC-3' for the amplification of Oct-4. For this, the embryos were washed with PBS, transferred to 30 µL of cold cell lysis buffer and incubated in a thermal cycler at 75�C for 10 min. The cell lysate was treated with DNase-I at 37�C for 30 min to degrade genomic DNA and then heated at 75�C for 5 min to inactivate the DNase-I. The cell lysate (10 µL) was used for making cDNA using random primer. The PCR cycle included heating to 94�C for 2 min, followed by 33 cycles of 94�C for 30 s, 57�C for 30 s, and 72�C for 45 s. A final extension at 72�C for 10 min was carried out to complete the amplification of the Oct-4 gene. Transcripts of Oct-4 were detected at all of the embryonic stages, from the 2-cell through the hatched blastocyst stage in both IVF and parthenogenetically generated embryos. These results indicate that Oct-4, which is believed to be a reliable marker for pluripotency of ESCs in a number of species, is expressed in early cleavage-stage buffalo embryos and continues to be expressed in preimplantation-stage blastocysts.

396 Oct-4 EXPRESSION IN CAT INNER CELL MASS-DERIVED CELLS CULTURED IN MEDIUM WITH DIFFERENT PROTEIN SOURCES

2010 ◽  
Vol 22 (1) ◽  
pp. 354
Author(s):  
T. S. Rascado ◽  
J. F. Lima-Neto ◽  
S. E. R. S. Lorena ◽  
B. W. Minto ◽  
F. C. Landim-Alvarenga
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Embryonic Stem Cell ◽  
Inner Cell Mass ◽  
Culture Media ◽  
Cell Mass ◽  
Embryonic Stem ◽  
Domestic Cat ◽  
Santa Cruz

The domestic cat can be used as a biological model for humans because of similarities in some disease and genetically transmitted conditions. Embryonic stem cells might complete nuclear reprogramming more efficiently than somatic cells and, therefore, are potentially useful for increasing interspecific cloning success. The objective of this study was to establish an effective culture system for inner cell mass (ICM)-derived cells in the domestic cat, testing the ability of the ICM to attach to the culture dish and to form embryonic stem cell colonies in the presence of fetal calf serum (FCS) and Knockout serum (KS). Moreover, knowing that the transcription factor Oct-4 is important for the maintenance of pluripotency in human and murine embryonic stem cells, the expression of this factor was evaluated in in vitro-produced blastocyst and in the attached ICM. Domestic cat oocytes were matured, fertilized, and cultured in vitro until the blastocyst stage. The ICM was mechanically isolated (n = 60) using a scalpel blade and transferred to a monolayer of chemically inactivated cat fibroblasts with 10 μg mL-1 mitomicin C. The base culture media (BM) was DMEM/F12 supplemented with nonessential amino acids, glutamine, leukemia inhibitory factor, fibroblast growth factor-2, 2-mercaptoethanol, and antibiotics. Three groups were tested: G1 = BM with 20% FCS (20); G2 = BM with 20% KS (20); G3 = BM with 15% FSC and 5% KS (20). Culture was performed in a 5% CO2 in air incubator at 38.5°C. No statistical difference was observed among groups in relation to ICM attachment (chi-square, P > 0.05). Ninety percent of the ICM presented good adhesion after 3 days of culture and started to grow in all media tested. However, until now, no good colonies were formed. Fifteen blastocysts and 10 attached ICM were fixed in 3% paraformaldehyde and permeabilized in 0.2% triton X-100 in PBS. Subsequently, to block nonspecific binding of the primary antibody, the preadsorption for 2 h at room temperature with OCT4 blocking peptide (sc-8628P, Santa Cruz Biotechnology, Santa Cruz, CA, USA) was used. Samples were incubated with Oct4 antibody (N-19 : sc 8628, Santa Cruz Biotechnology) and with the appropriate secondary antibody (A21431, Invitrogen) and examined by fluorescence microscopy. Oct4 protein was detected both in the ICM and trophoderm cells, and it was distributed in cytoplasm and nuclei. These embryos were also stained with Hoechst 33342. Although further standardization of the culture media is needed, it seems that the KS can be replaced by FCS in cat embryonic stem cell culture. Furthermore, the immunostain of the trophoderm with Oct-4 indicates a difference in the expression of this factor when compared with its expression on human and murine blastocysts. This could be related to in vitro production, or Oct 4 is not a good pluripotency marker for cat embryos and cat embryonic stem cell, consequently. This fact has been noted in goat, bovine, and porcine embryos. Acknowledgment is given to FAPESP.

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