Inactivated Sendai-virus-mediated fusion improves early development of cloned bovine embryos by avoiding endoplasmic-reticulum-stress-associated apoptosis

2011 ◽  
Vol 23 (6) ◽  
pp. 826 ◽  
Author(s):  
Bong-Seok Song ◽  
Ji-Su Kim ◽  
Seung-Bin Yoon ◽  
Kyu-Sun Lee ◽  
Deog-Bon Koo ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Er Stress ◽  
Early Development ◽  
Sendai Virus ◽  
Inner Cell Mass ◽  
Cell Mass ◽  
Donor Cell ◽  
Underlying Mechanism ◽  
Developmental Competence ◽  
Oocyte Activation

Somatic cell nuclear transfer (SCNT) is a powerful tool, not only for producing cloned animals, but also in revealing various early developmental events. However, relatively little is known regarding the biological events and underlying mechanism(s) directly associated with early development of SCNT embryos. Here, we show that production of high-quality bovine SCNT blastocysts is dependent on the method used for fusion and the associated reduction in endoplasmic reticulum (ER) stress. During fusion between the donor cell and the enucleated oocyte, electrofusion triggers spontaneous oocyte activation, accompanied by an increase in intracellular Ca2+ and improper nuclear remodelling. These events can be greatly reduced by the use of Sendai virus (SV)-mediated fusion. Moreover, SV-SCNT improves the blastulation rate and blastocyst quality, defined by the number and ratio of inner cell mass and trophectoderm cells in each blastocyst, in comparison with electrofusion-mediated SCNT (E-SCNT). Interestingly, expression of ER-stress-associated genes and blastomere apoptosis were significantly increased in E-SCNT embryos. These increases could be reversed by inhibition of ER stress or by using the SV-mediated fusion method. Collectively, these results indicate that SV-mediated fusion improves the developmental competence and quality of SCNT blastocysts, by reducing ER-stress-associated apoptosis.

58 ISOLATION OF BOVINE TROPHOBLAST AND ITS REPROGRAMMING BY NUCLEAR TRANSFER

2011 ◽  
Vol 23 (1) ◽  
pp. 134
Author(s):  
I. M. Saadeldin ◽  
B. H. Kim ◽  
B. Roibas da Torre ◽  
O. J. Koo ◽  
G. Jang ◽  
...  
Keyword(s):  
Nuclear Transfer ◽  
Inner Cell Mass ◽  
Quantitative Polymerase Chain Reaction ◽  
Cell Mass ◽  
Donor Cell ◽  
Developmental Competence ◽  
Control Group ◽  
Embryonic Cells ◽  
Blastocyst Development

Nuclear transfer (NT) has been used to produce many cloned offspring using several types of cells, including embryonic cells. Even though inner cell mass cells have been used as donor karyoplast for producing cloned animals, there are few studies using trophoblast. In mice, clones were born by nuclear transfer of trophoblasts from the expanded blastocyst into enucleated oocytes as a trial to show the totipotency of both inner cell mass and trophectoderm cells isolated from blastocysts (Tsunoda and Kato 1998 J. Reprod. Fertil. 113, 181–184). However, bovine trophoblast cell (TC) lines have not been used in NT to date. The purpose of this study was to elucidate whether TC as donor cell can be reprogrammed in bovine enucleated oocyte and determine the relative abundance of interferon tau (IFNτ) expression in the resulting cloned preimplantational embryos. Hatched blastocysts produced by IVF were used to isolate TCs on mouse embryonic fibroblasts treated with mitomycin C as feeder cells. TCs and adult fibroblasts (AF, control group for NT) were microinjected to perivitelline space of in vitro mature enucleated oocytes and electrically fused. Reconstructed embryos were chemically activated and cultured in a 2-step chemically defined medium. Levels of IFNτ expression in IVF-, TC-, and AF-derived blastocysts were analyzed using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). IVF produced embryos were used as reference to analyze the linear progressive expression of IFNτ through mid-, expanded, and hatching blastocysts. As a result, TCs expressing IFNτ were successfully isolated and cultured on feeder layers. It grew as cell sheets of cuboidal epithelium with high proliferation capacity as a single colony originated from a small clump of cells measured 0.5 cm within 7 days of culture. TCs were reprogrammed in the enucleated oocytes to blastocyst with similar efficiency to AF (14.5% and 15.6%, respectively; P ≤ 0.05). RT-qPCR studies showed that IFNτ expression was higher in TC-derived blastocysts than IVF- and AF-derived blastocysts. Both IVF- and TC-derived blastocysts, showed progressive increase of IFNτ expression through the advancement of blastocyst development when it was compared to AF-derived blastocysts. In conclusion, using TCs expressing IFNτ as donor cell for bovine NT could increase the developmental competence of cloned embryos as indicated by progressive linear increase in IFNτ expression. This study was supported by grants from IPET (#109023-05-1-CG000), NRF (#M10625030005-10N250300510), MKE (#2009-67-10033839, #2009-67-10033805), and BK21 program. Saadeldin I. M. is supported by Islamic Development Bank (IDB) merit scholarship, Jeddah, Saudi Arabia.

Iloprost supports early development of in vitro-produced porcine embryos through activation of the phosphatidylinositol 3-kinase/AKT signalling pathway

2017 ◽  
Vol 29 (7) ◽  
pp. 1306 ◽  
Author(s):  
Pil-Soo Jeong ◽  
Seung-Bin Yoon ◽  
Seon-A Choi ◽  
Bong-Seok Song ◽  
Ji-Su Kim ◽  
...  
Keyword(s):  
Early Development ◽  
Inner Cell Mass ◽  
Formation Rate ◽  
Cell Mass ◽  
Signalling Pathway ◽  
Developmental Competence ◽  
Dependent Manner ◽  
Phosphatidylinositol 3 Kinase ◽  
Phosphatidylinositol 3

Despite evidence of the presence of prostaglandin (PG) I2 in mammalian oviducts, its role in early development of in vitro-produced (IVP) embryos is largely unknown. Thus, in the present study we examined the effects of iloprost, a PGI2 analogue, on the in vitro developmental competence of early porcine embryos and the underlying mechanism(s). To examine the effects of iloprost on the development rate of IVF embryos, iloprost was added to the in vitro culture (IVC) medium and cultured for 6 days. Supplementation of the IVC medium with iloprost significantly improved developmental parameters, such as blastocyst formation rate, the trophectoderm : inner cell mass ratio and cell survival in IVF and parthenogenetically activated (PA) embryos. In addition, post-blastulation development into the expanded blastocyst stage was improved in iloprost-treated groups compared with controls. Interestingly, the phosphatidylinositol 3-kinase (PI3K)/AKT signalling pathway was significantly activated by iloprost supplementation in a concentration-dependent manner (10–1000 nM), and the beneficial effects of iloprost on the early development of porcine IVF and PA embryos was completely ablated by treatment with 2.5 μM wortmannin, a PI3K/AKT signalling inhibitor. Importantly, expression of the PI3K/AKT signalling pathway was significantly reduced in somatic cell nuclear transfer (SCNT) compared with IVF embryos, and iloprost supported the early development of SCNT embryos, as was the case for IVF and PA embryos, suggesting a consistent effect of iloprost on the IVC of IVP porcine embryos. Together, these results indicate that iloprost can be a useful IVC supplement for production of IVP early porcine embryos with high developmental competence.

Valproic acid enhances early development of bovine somatic cell nuclear transfer embryos by alleviating endoplasmic reticulum stress

2014 ◽  
Vol 26 (3) ◽  
pp. 432 ◽  
Author(s):  
Bong-Seok Song ◽  
Seung-Bin Yoon ◽  
Bo-Woong Sim ◽  
Young-Hyun Kim ◽  
Jae-Jin Cha ◽  
...  
Keyword(s):  
Valproic Acid ◽  
Endoplasmic Reticulum ◽  
Er Stress ◽  
Somatic Cell ◽  
Early Development ◽  
Somatic Cell Nuclear Transfer ◽  
Nuclear Transfer ◽  
Histone Deacetylase Inhibitors ◽  
Trichostatin A ◽  
Developmental Competence

Despite the positive roles of histone deacetylase inhibitors in somatic cell nuclear transfer (SCNT), few studies have evaluated valproic acid (VPA) and its associated developmental events. Thus, the present study was conducted to elucidate the effect of VPA on the early development of bovine SCNT embryos and the underlying mechanisms of action. The histone acetylation level of SCNT embryos was successfully restored by VPA, with optimal results obtained by treatment with 3 mM VPA for 24 h. Importantly, the increases in blastocyst formation rate and inner cell mass and trophectoderm cell numbers were not different between the VPA and trichostatin A treatment groups, whereas cell survival was notably improved by VPA, indicating the improvement of developmental competence of SCNT embryos by VPA. Interestingly, VPA markedly reduced the transcript levels of endoplasmic reticulum (ER) stress markers, including sXBP-1 and CHOP. In contrast, the levels of GRP78/BiP, an ER stress-alleviating transcript, were significantly increased by VPA. Furthermore, VPA greatly reduced cell apoptosis in SCNT blastocysts, which was further evidenced by the increased levels of the anti-apoptotic transcript Bcl-xL and decreased level of the pro-apoptotic transcript Bax. Collectively, these results suggest that VPA enhances the developmental competence of bovine SCNT embryos by alleviating ER stress and its associated developmental damage.

Induction of autophagy protects against extreme hypoxia-induced damage in porcine embryo

Reproduction ◽  
2021 ◽  
Vol 161 (4) ◽  
pp. 353-363
Author(s):  
Mun-Hyeong Lee ◽  
Pil-Soo Jeong ◽  
Bo-Woong Sim ◽  
Hyo-Gu Kang ◽  
Min Ju Kim ◽  
...  
Keyword(s):  
Oxygen Tension ◽  
Early Phase ◽  
Inner Cell Mass ◽  
Formation Rate ◽  
Cell Mass ◽  
Female Reproductive Tract ◽  
Developmental Competence ◽  
Early Embryos ◽  
Developmental Parameters

In the mammalian female reproductive tract, physiological oxygen tension is lower than that of the atmosphere. Therefore, to mimic in vivo conditions during in vitro culture (IVC) of mammalian early embryos, 5% oxygen has been extensively used instead of 20%. However, the potential effect of hypoxia on the yield of early embryos with high developmental competence remains unknown or controversial, especially in pigs. In the present study, we examined the effects of low oxygen tension under different oxygen tension levels on early developmental competence of parthenogenetically activated (PA) and in vitro-fertilized (IVF) porcine embryos. Unlike the 5% and 20% oxygen groups, exposure of PA embryos to 1% oxygen tension, especially in early-phase IVC (0–2 days), greatly decreased several developmental competence parameters including blastocyst formation rate, blastocyst size, total cell number, inner cell mass (ICM) to trophectoderm (TE) ratio, and cellular survival rate. In contrast, 1% oxygen tension did not affect developmental parameters during the middle (2–4 days) and late phases (4–6 days) of IVC. Interestingly, induction of autophagy by rapamycin treatment markedly restored the developmental parameters of PA and IVF embryos cultured with 1% oxygen tension during early-phase IVC, to meet the levels of the other groups. Together, these results suggest that the early development of porcine embryos depends on crosstalk between oxygen tension and autophagy. Future studies of this relationship should explore the developmental events governing early embryonic development to produce embryos with high developmental competence in vitro.

A method for obtaining chimaeric mouse blastocysts with two separate inner cell masses: a preliminary report

Development ◽  
1982 ◽  
Vol 71 (1) ◽  
pp. 215-221
Author(s):  
Andrzej K. Tarkowski ◽  
Marie Wojewodzka
Keyword(s):  
Relative Position ◽  
Preliminary Report ◽  
Sendai Virus ◽  
Inner Cell Mass ◽  
Cell Mass ◽  
Identical Twins ◽  
Foetal Membrane ◽  
Dual Origin

Pairs of zona-free mouse blastocysts aggregated in the presence of inactivated Sendai virus and subsequently cultured in vitro will fuse to form a chimaeric blastocyst with one common blastocoelic cavity. Depending on the relative position of the inner cell masses in the apposed ‘parental’ blastocysts, the resulting chimaeric blastocyst contains either a single inner cell mass (ICM) of dual origin or two discrete ICMs each originating from one embryo. In the present experiments, fusion between the two aggregated blastocysts occurred in 23% of the pairs and 64% of these chimaeric blastocysts contained two ICMs. Blastocysts of the latter type could potentially give rise to pairs of embryos which as regards the topography of the foetal membrane would resemble spontaneous identical twins, although they would be genetically dissimilar. Possible applications of the described method are discussed.

scholarly journals Selective Activation of Endoplasmic Reticulum Stress by Reactive-Oxygen-Species-Mediated Ochratoxin A-Induced Apoptosis in Tubular Epithelial Cells

2021 ◽  
Vol 22 (20) ◽  
pp. 10951
Author(s):  
Chong-Sun Khoi ◽  
Yu-Wen Lin ◽  
Jia-Huang Chen ◽  
Biing-Hui Liu ◽  
Tzu-Yu Lin ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Endoplasmic Reticulum ◽  
Er Stress ◽  
Ochratoxin A ◽  
Reactive Oxygen ◽  
Underlying Mechanism ◽  
Oxygen Species ◽  
Food And Feed ◽  
Renal Proximal Tubular Cells ◽  
Induced Apoptosis

Ochratoxin A (OTA), one of the major food-borne mycotoxins, impacts the health of humans and livestock by contaminating food and feed. However, the underlying mechanism of OTA nephrotoxicity remains unknown. This study demonstrated that OTA induced apoptosis through selective endoplasmic reticulum (ER) stress activation in human renal proximal tubular cells (HK-2). OTA increased ER-stress-related JNK and precursor caspase-4 cleavage apoptotic pathways. Further study revealed that OTA increased reactive oxygen species (ROS) levels, and N-acetyl cysteine (NAC) could reduce OTA-induced JNK-related apoptosis and ROS levels in HK-2 cells. Our results demonstrate that OTA induced ER stress-related apoptosis through an ROS-mediated pathway. This study provides new evidence to clarify the mechanism of OTA-induced nephrotoxicity.

178 IMPROVED DEVELOPMENTAL COMPETENCE OF BOVINE EMBRYOS BY PGI2 ANALOG TREATMENT

2006 ◽  
Vol 18 (2) ◽  
pp. 197 ◽  
Author(s):  
B. S. Song ◽  
J. S. Kim ◽  
D. B. Koo ◽  
J. S. Park ◽  
K. K. Lee ◽  
...  
Keyword(s):  
Inner Cell Mass ◽  
Culture Media ◽  
Cell Mass ◽  
Developmental Rate ◽  
Treated Group ◽  
Developmental Competence ◽  
Bovine Embryos ◽  
Frozen Semen ◽  
Oviductal Fluid

The microenvironment of the follopian tube, in which the oviductal fluid contains a variety of cytokines and growth factors, affects pre-implantation development of fertilized embryos in mammals. Prostaglandin I2 (PGI2, prostacyclin) exists in oviductal fluid and is synthesized from arachidonic acid by prostacyclin synthetase. PGI2 also enhances the implantation rate of mouse embryos. In this study, the effect of PGI2 analog on the development of bovine embryos was examined. Bovine cumulus oocytes complexes (COCs) were matured in TCM-199 medium supplemented with 10 IU/mL pregnant mare serum gonadotropin (PMSG), 10 IU/mL hCG, and 10 ng/mL epidermal growth factor (EGF) at 39�C, 5% CO2 in air for 20-22 h. Following in vitro maturation, COCs were fertilized in Fert-TALP medium containing 0.6% BSA using frozen semen. Also, oocytes matured in vitro were enucleated, individually reconstructed with bESF cells, fused, and then activated by treatment with 5 �M ionomycin for 5 min and 2 mM 6-DMAP for 4 h. In vitro-fertilized (IVF) and nuclear-transferred (NT) eggs were cultured in 50 ��L drops of CR1-aa medium supplemented with 0.3% BSA in the absence or presence of 1 �M PGI2 analog at 39�C, 5% CO2 in air, respectively. At 3 days of culture, cleaved embryos were further cultured in the same culture media supplemented with 10% FBS for 4 days. Allocations of blastocysts to inner cell mass (ICM) and trophoblast (TE) cells were investigated to assess embryo quality. All experiments were repeated more than three times. All data were analyzed by using the Duncan test of ANOVA by the Statistical Analysis System (SAS Institute, Inc., Cary, NC, USA) and numbers of nuclei in blastocysts were expressed as mean � SE. No difference was detected in the cleaved rate of the eggs between the treated- and nontreated groups. IVF zygotes treated with PGI2 analog represented a higher developmental rate (33%, 122/418) to the blastocyst stage than nontreated controls (24%, 107/456) (P < 0.05). Among IVF-derived blastocysts, interestingly, the proportion (46%, 84/181) of expanded blastocysts was significantly higher in the PGI2 analog-treated group compared with that in the nontreated group (28%, 46/164). The number of nuclei in (165 � 6.1, n = 15) in blastocysts in the PGI2 analog-treated group was higher than that (146.12 � 5.7, n = 18) in the nontreated group (P < 0.05). No difference was detected in the ratio of ICM to total cells between PGI2 analog-treated (42.0 � 3.0%) and nontreated groups (41.9 � 2.9%). Like the IVF embryos, NT embryos in the PGI2 analog-treated group showed a higher in vitro developmental rate (33.6%, 43/128) than the nontreated embryos (24.2%, 32/132) (P < 0.05). Our results indicate that PGI2 analog improves the kinetics of embryo development in cattle.

48 QUIESCENCE INDUCES LONG-TERM EPIGENETIC CHANGES IN BOVINE FIBROBLASTS THAT IMPROVE THEIR REPROGRAMMING INTO CLONED ANIMALS

2013 ◽  
Vol 25 (1) ◽  
pp. 171 ◽  
Author(s):  
P. K. Kallingappa ◽  
P. Turner ◽  
A. Green ◽  
J. Oliver ◽  
M. Eichenlaub ◽  
...  
Keyword(s):  
Rna Polymerase Ii ◽  
Inner Cell Mass ◽  
Cell Mass ◽  
Donor Cell ◽  
Enzyme Linked Immunosorbent Assay ◽  
Serum Starvation ◽  
Functional Assay ◽  
Epigenetic Changes ◽  
G1 Cells

Cloning by somatic cell nuclear transfer (SCNT) forces cells to lose their lineage-specific epigenetic marks and become totipotent again. This reprogramming process often results in epigenetic and transcriptional aberrations that compromise development. Development rates after SCNT can thus serve as a functional assay for genome-wide epigenetic reprogramming. Dolly the sheep, the first mammalian SCNT clone, was derived from a donor cell that was induced into quiescence by serum starvation. We hypothesized that quiescence alters the epigenetic status of donor cells and elevates their reprogrammability. To test this idea, we compared chromatin composition and cloning efficiency of serum-starved quiescent (G0) bovine adult male fibroblasts versus non-starved, diploid G1 controls. Mechanically synchronized G1 cells were generated by manual selection or mitotic shake-off and processed within 3 h post-mitosis. Based on morphological assessment and 5-ethyl-2′-deoxyuridine (EdU) incorporation during continuous labelling, >93% of cells were captured in G1. Using quantitative confocal immunofluorescence microscopy and fluorometric enzyme-linked immunosorbent assay (ELISA), we show that G0 fibroblasts were significantly hypomethylated at lysines (K) of histone 3 (H3), specifically H3K4me3, H3K9me2, H3K9me3, and H3K27me3, but not H3K9me1. They were also significantly hypoacetylated at H3K9 and H4K5, hyperacetylated at H4K12, and unchanged at H4K16 positions. Furthermore, G0 cells significantly down-regulated the nuclear abundance of RNA polymerase II, histone variant H2A.Z, as well as polycomb group proteins EED, SUZ12, PHC1, and RING2. Following NT into metaphase-arrested oocytes, G0 chromatin condensed slower than that of G1 cells, indicating a more relaxed configuration. After 7 days of in vitro culture, H3K9me3, but not H4K4me3, H3K27me3, SUZ12, and RING2, remained hypomethylated in G0- versus G1-derived NT blastocysts, both in the inner cell mass and trophectoderm (730 v. 550 nuclei from 55 v. 42 G0 v. G1 blastocysts, respectively; n = 7 NT runs). Reduced H3K9me3 levels correlated with significantly increased mRNA abundance of the H3K9me3-specific histone demethylase KDM4B (or JMJD2B) in NT blastocysts. Expression of other pluripotency-related factors (NANOG, SOX2, STELLA, and IIFITM3), imprinted genes (SNRPN), and histone demethylases (KDM4A) was not affected in G0-derived blastocysts (32 G0 v. 55 G1 blastocysts; n = 4). Following NT, G0 donors developed significantly better into cloned blastocysts (175/382 = 46% v. 122/332 = 37% for G0 v. G1, respectively; n = 7, P < 0.05). Likewise, after transfer into surrogate mothers, G0-derived blastocysts developed significantly better into live calves (5/18 = 28% v. 1/25 = 4% for G0 v. G1, respectively; n = 2, P < 0.05). In conclusion, quiescence induced long-term epigenetic changes, specifically H3K9me3 hypomethylation, that correlated with increased donor cell reprogrammability. This research was supported by FRST C10X0303.

148 EFFECTS OF CAFFEINE SUPPLEMENTATION ON BOVINE OOCYTE DEVELOPMENTAL CAPACITY

2017 ◽  
Vol 29 (1) ◽  
pp. 182
Author(s):  
S. M. Bernal-Ulloa ◽  
A. Lucas-Hahn ◽  
P. Aldag ◽  
D. Herrmann ◽  
U. Baulain ◽  
...  
Keyword(s):  
Inner Cell Mass ◽  
Mammalian Species ◽  
Cell Mass ◽  
Phosphodiesterase Inhibitor ◽  
Developmental Competence ◽  
Differential Staining ◽  
Final Phase ◽  
Cell Numbers ◽  
Developmental Capacity

Oocyte culture in the presence of the nonspecific competitive phosphodiesterase inhibitor caffeine has been reported to increase developmental capacity of oocytes in different mammalian species. Here, we evaluated the effects of caffeine supplementation during the final phase of in vitro maturation (IVM) on developmental rates and blastocyst cell numbers. Bovine ovaries were collected from a local abattoir. A total of 1142 cumulus-oocyte-complexes were obtained by slicing. Cumulus-oocyte complexes were either in vitro matured for 24 h (Standard) or matured for 20 h followed by additional culture for 6 h in fresh IVM medium supplemented with 10 mM caffeine (Caffeine 6 h). In vitro fertilization was performed for 19 h using frozen-thawed sperm from 2 different bulls. After IVF, presumptive zygotes were cultured in vitro for 8 days until the blastocyst stage. Cleavage and blastocyst rates were evaluated 3 and 8 days after IVF, respectively. Expanded blastocysts from the different treatments were submitted to differential staining. SAS/STAT software (SAS Institute Inc., Cary, NC, USA) was used to evaluate cleavage and blastocyst rates using the Glimmix procedure and blastocyst cell numbers were compared using the linear model procedure. Cleavage rates were lower using caffeine for bull B and blastocyst production decreased for bull A. Caffeine treatment increased inner cell mass (ICM) number for bull B and decreased trophectoderm (TE) and total cell numbers for bull A. However, similar TE and total cells were obtained for bull B (Table 1; P < 0.05). Results show that developmental competence can be affected by caffeine supplementation at the final phase of IVM probably due to oocyte-sperm interaction changes. Table 1. In vitro developmental competence of oocytes cultured with caffeine at the end of IVM

Morphology, developmental stages and quality parameters of in vitro-produced equine embryos

2019 ◽  
Vol 31 (12) ◽  
pp. 1758 ◽  
Author(s):  
Elaine M. Carnevale ◽  
Elizabeth S. Metcalf
Keyword(s):  
Embryo Development ◽  
Developmental Stages ◽  
Inner Cell Mass ◽  
Early Stage ◽  
Cell Mass ◽  
Quality Parameters ◽  
Early Embryo ◽  
Developmental Competence ◽  
Limited Information

Intracytoplasmic sperm injection (ICSI) is used to produce equine embryos invitro. The speed of embryo development invitro is roughly equivalent to what has been described for embryos produced invivo. Morphological evaluations of ICSI-produced embryos are complicated by the presence of debris and the dark nature of equine embryo cytoplasm. Morulas and early blastocysts produced invitro appear similar to those produced invivo. However, with expansion of the blastocyst, distinct differences are observed compared with uterine embryos. In culture, embryos do not undergo full expansion and thinning of the zona pellucida (ZP) or capsule formation. Cells of the inner cell mass (ICM) are dispersed, in contrast with the differentiated trophoblast and ICM observed in embryos collected from uteri. As blastocysts expand invitro, embryo cells often escape the ZP as organised or disorganised extrusions of cells, probably through the hole incurred during ICSI. Quality assessment of invitro-produced early stage equine embryos is in its infancy, because limited information is available regarding the relationship between morphology and developmental competence. Early embryo development invivo is reviewed in this paper, with comparisons made to embryo development invitro and clinical assessments from a laboratory performing commercial ICSI for &gt;15 years.

Sign in / Sign up

Export Citation Format

Share Document