Development in vitro and in vivo of aggregated parthenogenetic bovine embryos

1995 ◽  
Vol 7 (5) ◽  
pp. 1073 ◽  
Author(s):  
A Boediono ◽  
S Saha ◽  
C Sumantri ◽  
T Suzuki
Keyword(s):  
Cytochalasin B ◽  
Polar Body ◽  
Cleavage Rate ◽  
Development In Vitro ◽  
Second Polar Body ◽  
Bovine Oocytes ◽  
Longitudinal Diameter ◽  
Parthenogenetic Embryos

Mature bovine oocytes were activated with 7% ethanol followed by cytochalasin B or D treatment. Most oocytes extruded a second polar body and formed one pronucleus when treated with 7% ethanol alone [35/43 (81%)]. With ethanol followed by cytochalasin B or D, overall activation frequency was 70% (309/441), with activated oocytes containing two pronuclei. The cleavage rate was not significantly different between treatment with ethanol alone and ethanol followed by 5 micrograms mL-1 cytochalasin B, but it was significantly lower than in fertilized oocytes (P < 0.01). However, the blastocyst production rate was significantly different (P < 0.01) among the treatments. The incidence of parthenogenetic embryos with normal (diploid) complements and with chromosome anomalies (2N/4N) was 68% (17/25) and 32% (8/25) respectively, and this was not affected by cryopreservation treatment. The longitudinal diameter of aggregated-four embryos cultured in vitro was greater (P < 0.01) than aggregated-two or single embryos. One of the aggregated-four parthenogenetic embryos was further cultured in vitro and developed up to Day 27 after activation, with a diameter of 2980 microns. The aggregated-four parthenogenetic embryos were transferred to five recipients. The oestrus was prolonged in three recipients and they returned to oestrus on Day 57, 62 and 67 after the previous oestrus. These results indicate that aggregating parthenogenetic embryos can prolong their survival in vitro and in vivo.

44 IN VITRO DEVELOPMENT OF INTERSPECIES NUCLEAR TRANSFER EMBRYOS GENERATED WITH BOVINE OOCYTES AND EQUINE SKIN FIBROBLASTS

2011 ◽  
Vol 23 (1) ◽  
pp. 128
Author(s):  
J. Lee ◽  
J. Park ◽  
Y. Chun ◽  
W. Lee ◽  
K. Song
Keyword(s):  
Nuclear Transfer ◽  
Polar Body ◽  
Donor Cell ◽  
Skin Fibroblasts ◽  
Developmental Competence ◽  
Cleavage Rate ◽  
Cell Stage ◽  
Bovine Oocytes

Study for equine somatic cell nuclear transfer (SCNT) is an attractive field for research, but it has not been a major field of study because it is hard to obtain a sufficient number of ovaries and it takes a lot of time and effort for the recovery of oocytes matured in vivo by ovum pickup. It was reported that the bovine cytoplast could support the remodelling of equine donor cells (Zhou et al. 2007 Reprod. Domest. Anim. 42, 243–247). The objectives of this study are 1) to monitor the early events of equine SCNT by interspecies SCNT (isSCNT) between bovine cytoplast and equine donor cell, and 2) to investigate the developmental competence of isSCNT embryos. Bovine oocytes were recovered from the follicles of slaughtered ovaries, and matured in TCM-199 supplemented with 10 mU mL–1 FSH, 50 ng mL–1 EGF, and 10% FBS at 39°C under 5% CO2 in air for 22 h. Fibroblasts derived from bovine or equine skin tissues were synchronized at G0/G1 stage by contact inhibition for 72 h. After IVM, oocytes with polar body were enucleated and electrically fused with equine or bovine skin fibroblasts (1.0 kV cm–1, 20 μs, 2 pulses). Fused couplets were activated with 5 μM ionomycin for 4 min followed by 5 h culture in 10 μg mL–1 cycloheximide (CHX) and/or 2 mM 6-DMAP, and cultured in modified synthetic oviduct fluid (mSOF) at 39°C under 5% CO2, 5% O2, and 90% N2 for 7 days. All analyses were performed using SAS (version 9.1; SAS Institute, Cary, NC, USA). The cleavage rate of isSCNT embryos derived from equine cell was not different (252/323, 78.7%; P = 0.94) from that of SCNT embryos derived from bovine cell (230/297, 79.2%). However, the rate of isSCNT embryos developed to over 8-cell stage was lower (3.3%; P < 0.0001) than that of bovine SCNT embryos (39.4%), and total cell number of isSCNT embryos developed to over 8-cell stage was lower (17.5, n = 12; P < 0.0001) than that (80.8, n = 110) of bovine SCNT embryos. Also, the rate of blastocyst formation of isSCNT embryos (0/323; 0.0%) was lower (P < 0.0001) than that of bovine SCNT embryos (83/297; 29.3%). Meanwhile, reconstructed oocytes for isSCNT were fixed at 8 h after activation to investigate the formation of pseudo-pronucleus (PPN) after post-activation treatment with CHX or CHX+6-DMAP. The ratio of oocytes with single PPN after treatment with CHX+6-DMAP (26/35; 74.3%) was not different (P = 0.63) from that of oocytes treated with CHX (24/36; 68.1%). Although isSCNT embryos derived from bovine cytoplast and equine donor cell could not develop to more than the 16-cell stage, it is believed that the results of this isSCNT study could be used for the preliminary data regarding the reprogramming of donor cell in equine SCNT.

scholarly journals Developmental competence in vivo and in vitro of in vitro-matured equine oocytes fertilized by intracytoplasmic sperm injection with fresh or frozen-thawed spermatozoa

Reproduction ◽  
2002 ◽  
pp. 455-465 ◽  
Author(s):  
YH Choi ◽  
CC Love ◽  
LB Love ◽  
DD Varner ◽  
S Brinsko ◽  
...  
Keyword(s):  
Intracytoplasmic Sperm Injection ◽  
Polar Body ◽  
Cumulus Cells ◽  
Fertilization Rate ◽  
Developmental Competence ◽  
Cleavage Rate ◽  
First Polar Body ◽  
Bovine Oocytes

This study was undertaken to evaluate the development of equine oocytes in vitro and in vivo after intracytoplasmic sperm injection (ICSI) with either fresh or frozen-thawed spermatozoa, without the use of additional activation treatments. Oocytes were collected from ovaries obtained from an abattoir and oocytes classified as having expanded cumulus cells were matured in M199 with 10% fetal bovine serum and 5 microU FSH ml(-1). After 24-26 h of in vitro maturation, oocytes with a first polar body were selected for manipulation. Fresh ejaculated stallion spermatozoa were used for the experiment after swim-up for 20 min in sperm-Tyrode's albumen lactate pyruvate. Frozen-thawed spermatozoa from the same stallion were treated in a similar way. Spermatozoa were immobilized and injected into the oocytes using a Piezo drill. Presumptive zygotes were cultured in G1.2 medium for 20 or 96 h after the injection was administered, or were transferred to the oviducts of recipient mares and recovered 96 h later. In addition, bovine oocytes with first polar bodies were injected with the two types of stallion spermatozoa and fixed 20 h after injection to examine pronuclear formation. Fertilization rate (pronucleus formation and cleavage) at 20 h after injection of spermatozoa was not significantly different between fresh and frozen-thawed sperm groups in either equine or bovine oocytes. Pronucleus formation after injection of spermatozoa into bovine oocytes was significantly higher than that for equine oocytes (P < 0.05). There were no significant differences in cleavage rate or average number of nuclei at 96 h between equine oocytes injected with fresh or frozen-thawed spermatozoa. However, embryos developed in vivo for 96 h had a significantly higher number of nuclei in both sperm treatments compared with those cultured in vitro. These results indicate that good activation rates may be obtained after injection of either fresh or frozen-thawed equine spermatozoa without additional activation treatment. Injection of frozen-thawed equine spermatozoa results in similar embryo development to that obtained with fresh equine spermatozoa. In vitro culture of equine zygotes in G1.2 medium results in a similar cleavage rate but reduced number of cells compared with in vivo culture within the oviduct. Bovine oocytes may be useful as models for assessing sperm function in horses.

188 HAPLOID ACTIVATION OF BOVINE OOCYTES WITH IONOMYCIN AND SINGLE OR COMBINED ACTIVATING AGENTS

2016 ◽  
Vol 28 (2) ◽  
pp. 225 ◽  
Author(s):  
M. Suvá ◽  
N. G. Canel ◽  
D. F. Salamone
Keyword(s):  
Embryo Development ◽  
Polar Body ◽  
Reproductive Technologies ◽  
Mitogen Activated Protein Kinase ◽  
Cleavage Rate ◽  
Extrusion Rate ◽  
Second Polar Body ◽  
Polar Body Extrusion ◽  
Bovine Oocytes

Haploid activation of bovine oocytes is important for reproductive technologies such as intracytoplasmic sperm injection (ICSI) or somatic cell nuclear transfer (SCNT). Nevertheless, it is still a highly inefficient procedure. The aim of this work was to combine different activation drugs, known to have different targets along the activation cascade, to find a more effective activation protocol. Cumulus-oocyte complexes (COC) were aspirated from slaughtered ovaries and in vitro-matured (IVM) for 22 h. Oocytes were activated with 5 µM ionomycin (IO) for 4 min and then randomly allocated into 1 of the following treatments: 50 µM roscovitine (ROSC), 10 µg mL–1 cycloheximide (CHX), ROSC and 10 µM PD0325901 (ROSC/PD), or CHX and PD (CHX/PD) for 5 h; 15 µM dehydroleucodine (DHL) or DHL and ROSC (DHL/ROSC) for 3 h; DHL and CHX for 3 h followed by 2 h with CHX; 5-min exposure to 7% ethanol 4 h post-IO (ET); or ET followed by ROSC (ET-ROSC). Controls were IO followed by 3 h of exposure to 1.9 mM 6-DMAP with or without a previous 3-h culture in TCM-199 (3 h in DMAP and DMAP, respectively). Embryos were cultured in SOF medium. Pronuclear formation (PN) and second polar body extrusion (2PB) were assessed by 5 µg mL–1 propidium iodide oocyte staining, 17 h after IO. Activation was defined as the presence of at least 1 PN, and 2PB extrusion rate was calculated regardless of the nuclear stage. Data were analysed by Fisher’s Test (P < 0.05). Activation (Table 1) was similar in all groups, with the exception of ROSC/PD and ET-ROSC that were the highest and DHL that was the lowest. Although ROSC or CHX seemed to improve 2PB rate when combined with DHL, cleavage decreased significantly, suggesting DHL itself, or its combination with these drugs, negatively affects embryo development. Group ET showed activation rates comparable to other treatments, but it was not reflected on cleavage, suggesting that ET induces PN formation but it might be inefficient to trigger embryo development. Nevertheless, this observation was not made for ET-ROSC, as it showed a higher cleavage rate than ET and ROSC alone. The mitogen-activated protein kinase (MAPK) inhibitor PD showed different effects when combined with ROSC or CHX, despite that they both act on the mammary fat pad (MPF). In ROSC/PD, a slight improvement was observed on activation and cleavage rates compared with ROSC. Group CHX/PD resulted in a slightly higher 2PB percentage, but a lower activation percentage that derived in a significantly lower cleavage than CHX. In conclusion, ROSC and CHX were the most effective single treatments for haploid activation. Moreover, some combined treatments, namely DHL/ROSC and DHL/CHX, proved to be as effective or better at 2PB extrusion rate, which is the defining feature in haploid activation. Table 1.Activation, second polar body extrusion (2PB) and cleavage of bovine oocytes activated with ionomycin followed by single or combined activating agents1

scholarly journals 77CLONED EMBRYO DEVELOPMENT IN VITRO: COMPARISON OF CONVENTIONAL AND INDUCED ENUCLEATION PROCEDURES FOR BOVINE CYTOPLAST PREPARATION

2004 ◽  
Vol 16 (2) ◽  
pp. 160
Author(s):  
M.-K. Wang ◽  
E.W. Overstrom
Keyword(s):  
Embryo Development ◽  
Polar Body ◽  
Blastocyst Stage ◽  
In Vitro Development ◽  
Uv Illumination ◽  
Development In Vitro ◽  
Second Polar Body ◽  
Vitro Development

Induced enucleation (IE) of oocytes with demecolcine produces competent ooplasts for SCNT as demonstrated previously in mouse, goat, cow and pig. Whether bovine IE cytoplasts are more or less competent than conventionally enucleated MII oocytes to support nuclear reprogramming of somatic chromatin and embryo development in vitro is not known. This study compared in vitro development of cloned bovine embryos produced by conventional and IE enucleation methods. Three experimental groups were: (1) Parthenogenetic controls. In vitro-matured, MII-arrested bovine oocytes were activated by a single (1×Act, 10μM ionomycin in Tyrodes-HEPES, 5min) or double activation (2×Act; 1×Act, wash 5min, 10μgmL−1 cycloheximide [CHX] 20min, repeat 1×Act) followed by incubation in CHX and 5μgmL−1 cytochalasin B (CB) for 6h, and then culture (BARC medium) for 7 days. (2) Conventional SCNT. MII oocytes were enucleated by micromanipulation in HEPES-buffered enucleation medium (BARC containing 7.5μgmL−1 CB, 5μgmL−1 Hoechst 33342, 10% FBS) under UV illumination (3–5s). Donor cells (fibroblasts, passage 7–9) were inserted into the perivitelline space, and the reconstructed couplets activated (1×Act). Reconstructed couplets were then electrofused, placed in BARC medium containing 10μgmL−1 CHX and 5μgmL−1 CB (6h), and then cultured for 7 days. (3) IE SCNT. MII oocytes were activated (1×Act), placed into BARC-5% FBS containing 0.4μgmL−1 demecolcine (DEME), 10μgmL−1 CHX, 2μgmL−1 cytochalasin D for 20min, then 20min without DEME, then returned to DEME. At 1–1.5h post-activation, the extruding second polar body (PB2) containing nuclear chromatin was removed by micromanipulation, couplets were reconstructed and fused as above, and additionally activated (two pulses, 20–30V/mm, 20μs). Embryos were cultured in 10μgmL−1 CHX and 5μgmL−1 CB medium for 4–5 hour, then BARC for 7 days. The results (Table 1) reveal that 2×Act increases embryo development at Day 2, but not Day 7. Further, there are no significant differences in embryo development rates between conventional and IE SCNT protocols. Respectively, 46%, 32% and 21% of cleaved control (1×Act), conventional and IE embryos developed to 16 cells on Day 7. In vitro development of cleavage embryos to the blastocyst stage was greater in controls (25–32%) than in conventional (22%) and IE (17%) SCNT groups on Day 7. Further comparisons of in vivo development between conventional and IE SCNT methods following embryo transfer are warranted. Supported by ACT, Cyagra and USDA NRI \#2001-35205-09966. Table 1 Embryo development: Conventional v. induced enucleation

Induction of triploidy in the mouse by cytochalasin B

Development ◽  
1975 ◽  
Vol 34 (2) ◽  
pp. 279-289
Author(s):  
Anna Niemierko
Keyword(s):  
Culture Medium ◽  
Cytochalasin B ◽  
Sex Chromosome ◽  
Polar Body ◽  
Cell Number ◽  
Second Polar Body ◽  
And Control ◽  
Mouse Eggs

Mouse eggs fertilized in vivo were treated with cytochalasin B in vitro (5 μg/ml of culture medium) at he moment of extrusion of the second polar body (2·5, 3·0, 3·5 h after copulation). Cytochalasin B inhibits cytokinesis of the second maturation division, so that triploid digynic eggs are formed in over 50% of treated eggs. Triploid eggs were transplanted to the oviducts of recipients. On the 4th and 5th day of development 41·7% of transplanted eggs were recovered. All embryos recovered on the 4th day were morulae, while on the 5th day blastocysts predominated. Recovered embryos were studied for cell number and ploidy. Twenty-three of 27 embryos with analysable metaphase plates were triploid and four were diploid (the latter were found in females into which both triploid and control diploid eggs were transplanted). Sex chromosome constitution was determined in seven cases: four triploids were XXY and three were XXX.

228 microRNA REGULATION OF GENES IN BOVINE OOCYTES AND EMBRYOS

2010 ◽  
Vol 22 (1) ◽  
pp. 272
Author(s):  
J. P. Barfield ◽  
G. J. Bouma ◽  
G. E. Seidel Jr
Keyword(s):  
Mirna Expression ◽  
Polar Body ◽  
Prostaglandin F2α ◽  
Defined Medium ◽  
Tight Junction Formation ◽  
First Polar Body ◽  
Lysis Buffer ◽  
Bovine Oocytes

Little is known about expression of microRNA (miRNA) in bovine oocytes and pre-implantation embryos. These molecules likely have an important role in regulating development. For example, differences in quality of oocytes matured in vivo v. in vitro might be due, in part, to altered miRNA expression. In Experiment 1, in vivo-matured COC were collected by transvaginal aspiration of 7 superstimulated cows 21 to 23 h after GnRH injection, given 48 h after prostaglandin F2α and the last of 6 FSH injections given b.i.d. Oocytes aspirated from abattoir ovaries were matured in vitro for 23 h in a chemically defined medium. After vortexing, maturation of both groups of oocytes was confirmed by visualization of the first polar body, and oocytes were snap frozen in mirVana lysis buffer (Applied Biosciences, Foster City, CA, USA). In Experiment 2, in vitro-matured oocytes were generated as described. Subsets were fertilized in vitro or activated parthenogenetically by incubation in 5-μM ionomycin for 5 min followed by 10 μg mL-1 cycloheximide plus 5 μg mL-1 cytochalasin B for 5 h. After 18 h and 12 h, respectively, fertilized and activated oocytes were centrifuged at 10 000 × g for 10 min to enable visualization of pronuclei. Zygotes with 2 polar bodies and 2 pronuclei and parthenotes with 2 pronuclei were snap frozen in mirVana lysis buffer. Total RNA was extracted from 30 pooled oocytes for each replicate using the mirVana MiRNA Isolation Kit (Ambion, Inc., Austin, TX, USA). Reverse transcription of RNA was performed using the QuantiMir RT kit (System Biosciences, Mountain View, CA, USA), and miRNA expression was evaluated by real-time PCR using the Mouse miRNome Profiler plate, which contains primers for 384 miRNA (System Biosciences). Three plates were analyzed for each group (30 oocytes per plate). Changes in relative expression levels were analyzed with a t-test of values normalized to miR-181a, which was consistently expressed in all samples. In Experiment 1, compared with in vitro-matured oocytes, in vivo-matured oocytes had 11-fold higher (P = 0.02) expression of miR-375, which targets numerous genes involved in electron transport chain and oxidative phosphorylation pathways according to the bioinformatic database mirGator. MiR-291a-5p, miR-494, miR-539, and miR-547 were expressed in in vivo-matured oocytes only; the converse was found for miR-575-5p. Results from Experiment 2 are in the table. Major pathways associated with potential targets of the detected miRNA include TGF-beta signaling, Wnt signaling, tight junction formation, DNA replication reactome, steroid biosynthesis, mRNA processing binding reactome, and glutamate metabolism. Several of these candidate miRNA might be important for regulation of bovine oocyte maturation and embryo development. Table 1.Experiment 2: Fold change expression of miRNA

scholarly journals 271 ASSESSMENT OF NUCLEAR STATUS OF ACTIVATED BOVINE OOCYTES MATURED IN DIFFERENT MATURATION CONDITIONS IN VITRO

2005 ◽  
Vol 17 (2) ◽  
pp. 285
Author(s):  
J.I. Park ◽  
Y. Jang
Keyword(s):  
Oocyte Maturation ◽  
Polar Body ◽  
Calf Serum ◽  
Chi Square ◽  
Cell Stage ◽  
Maturation Medium ◽  
Second Polar Body ◽  
Humidified Air ◽  
Bovine Oocytes

This study was carried out to assess the nuclear status after parthenogenetic activation in in vitro matured oocytes under different conditions. Bovine ovaries were collected from slaughtered cows at a local abattoir. Oocytes were aspirated from follicles of 3–8 mm in diameter and transferred to maturation medium: tissue culture medium (TCM)-199 supplemented with 10% (v/v) fetal calf serum, 100 mg/mL l-cysteine, 20 mg/mL sodium pyruvate, gonadotropins (each 250 IU of eCG and hCG/mL), and 10 mg/mL epidermal growth factor, with or without 5 mM hypotaurine and taurine. Oocytes were cultured at 38.9°C in 5% CO2 in humidified air. After 24 h of culture, oocytes with polar body were selected and submitted to activation treatments. Oocytes were exposed to calcium ionomycin (5 μM for 5 min) followed by incubation with 6-DMAP (2 mM), roscovitine (50 μM), or 6-DMAP + roscovitine for 3.5 h. After activation, oocytes were cultured in mSOF medium containing 0.8% BSA at 38.9°C in 5% CO2, 5% O2 in humidified air for 16 h and stained with Hoechst 33342 or aceto-orcein for assessment of nuclear status. Nuclear status was recorded as follows: 1PB (polar body) + 1PN (pronucleus), 2PB + 1PN and others. Data were analyzed using chi-square test. The maturation rate of bovine oocytes cultured in maturation medium containing hypotaurine/taurine (89.3%, n = 84) was higher (P < 0.05) than those cultured without hypotaurine/taurine (72%, n = 93). In the oocytes matured with hypotaurine/taurine, the rates of diploid activation (1PB + 1PN) were 84% (n = 50) in oocytes treated with 6-DMAP + roscovitine, 78.6% (n = 56) with 6-DMAP, and 52% (n = 50) with roscovitine. In the oocytes matured without hypotaurine/taurine, the rates of diploid activation were 80% (n = 60) in oocytes treated with 6-DMAP + roscovitine, 72% (n = 50) with 6-DMAP, and 54% (n = 50) with roscovitine. The rates of diploid activation were not different in oocytes matured with or without hypotaurine/taurine and among activation treatments. The oocytes treated with roscovitine showed a lower rate (P < 0.05) of diploid activation and higher rate (39.3–40%) of second polar body extrusion (1PN + 2PB) than the other activation groups in both maturation conditions. Cleavage rates to 2-cell stage were 40–45% in all groups. Development rate of blastocysts were 7–10% in all the groups treated with 6-DMAP and 6-DMAP + roscovitine and no blastocysts were obtained from the groups treated with roscovitine alone. Hypotaurine/taurine are known to be stable and potent antioxidants, and have shown the properties of supporting oocyte maturation and further embryonic development (Guerin and Menezo 1995 Zygote 3, 333–43; Mizushima and Fukui 2001 Theriogenology 55, 1432–45). In this study, although the effectiveness of hypotaurine/taurine on promoting oocyte maturation was observed, there were no significant improvements in the rate of diploid activation in oocytes matured with hypotaurine/taurine. These results suggest that the nuclear status of activated oocytes may not have a direct relationship with the enhanced maturation condition. This work was supported by BioGreen 21 Program(#1000520030100000-1), Republic of Korea.

133 VITRIFICATION CAUSES DAMAGE OF THE ANTIOXIDANT DEFENSE SYSTEM IN IVM PORCINE OOCYTES

2007 ◽  
Vol 19 (1) ◽  
pp. 184 ◽  
Author(s):  
T. Somfai ◽  
M. Ozawa ◽  
J. Noguchi ◽  
H. Kaneko ◽  
K. Ohnuma ◽  
...  
Keyword(s):  
Polar Body ◽  
Antioxidant Defense System ◽  
Blastocyst Stage ◽  
Developmental Competence ◽  
Control Group ◽  
Cleavage Rate ◽  
Sperm Penetration ◽  
Second Polar Body ◽  
Polar Body Extrusion

The present study investigated the ability of in vitro-matured (IVM) porcine oocytes to be fertilized in vitro after vitrification. Oocytes matured in vitro for 46 h according to Kikuchi et al. (2002 Biol. Reprod. 66, 1033–1041) were cryopreserved by solid surface vitrification (SSV; Dinnyes et al. 2000 Biol. Reprod. 63, 513–518) or subjected to the steps of SSV without cooling (toxicity control, TC). Oocyte viability was assessed 2 h after treatment by morphology and fluorescein diacetate staining. Live oocytes were in vitro-fertilized (IVF) and cultured (IVC) for 6 days according to Kikuchi et al. (2002). Fertilization and pronuclear development of oocytes were assessed 10 h after IVF by aceto-orcein staining. Cleavage and blastocyst rates were recorded during IVC. Glutathione (GSH) and hydrogen peroxide levels in oocytes were analyzed by DTNB-glutathione disulfide reductase recycling assay and 20,70-dichlorofluorescein fluorescence assay, respectively. Data were analyzed by ANOVA and paired t-test. The rate of live oocytes after SSV was lower compared to the control and the TC groups (54.4%, 100%, and 100%, respectively; P &lt; 0.05). Sperm penetration rates of SSV oocytes were lower than those of the control group (51.9% and 67.8%, respectively; P &lt; 0.05). Significantly fewer penetrated oocytes in the SSV group formed male pronuclei than those in the control and the TC groups (66.7%, 96.5%, and 98.5%, respectively; P &lt; 0.05). There were no differences in second polar body extrusion and monospermy rates between the treatment groups. The cleavage rate of SSV oocytes was significantly lower than that of the control and the TC groups (13.3%, 46.6%, and 47.7%, respectively; P &lt; 0.05). Blastocyst rates of control and TC oocytes were similar (20.7% and 23.6%, respectively), whereas only a single embryo developed to the blastocyst stage in the SSV group. GSH content of SSV oocytes was significantly lower than that of the control oocytes (7.3 pM and 10.5 pM, respectively), whereas the peroxide level was higher in SSV oocytes than in the control oocytes (59.0 and 50.5 FIU, respectively; P &lt; 0.05). Our results reveal a cryopreservation-related drop of intracellular GSH level in oocytes, which may cause their decreased ability to form a male pronucleus and their increased sensitivity to oxidative stress. These factors might contribute to the low developmental competence of vitrified oocytes. This work was supported by a grant-in-aid for the Japanese Society for the Promotion of Science Postdoctoral Fellowship for Foreign Researchers (P05648) and the Bilateral Scientific and Technological Collaboration Grant between Hungary and Japan (TET, no. JAP-11/02).

21 EFFECT OF SEVERAL PARAMETERS ON PARTHENOGENETIC BOVINE EMBRYO DEVELOPMENT IN VITRO

2006 ◽  
Vol 18 (2) ◽  
pp. 119
Author(s):  
S. Arat ◽  
H. Bagis ◽  
A. Tas ◽  
T. Akkoc
Keyword(s):  
Embryo Development ◽  
Development Rate ◽  
Electrical Pulse ◽  
Bovine Embryo ◽  
Cleavage Rate ◽  
The Third ◽  
Parthenogenetic Embryo ◽  
Development In Vitro ◽  
Parthenogenetic Embryos

The activation of oocytes is one of the most important steps for a successful cloning and has great importance on embryo development in vitro. The objective of this study was to examine the different parameters affecting parthenogenetic embryo development in vitro. In the first experiment, two activation protocols were compared to examine the effect of electrical pulse on activation. Bovine oocytes isolated from slaughterhouse ovaries were matured in TCM-199 supplemented with fetal bovine serum (FBS), sodium pyruvate, penicillin/streptomycin, rat insulin-like growth factor (rIGF-1), bovine follicle-stimulating hormone (bFSH), and bovine luteinizing hormone (bLH). A group of oocytes was exposed to a DC pulse of 133 V/500 �m for 25 �s, and then activated by calcium ionophore (5 �M) for 10 min, cytochalasin D (CD) (2.5 �g/mL) + cycloheximide (CHX, 10 �g/mL) for 1 h, and CHX alone for 5 h (Group 1). Another group of oocytes was activated only by chemicals without electrical pulse. Activated oocytes were cultured for 72 h in G1-3 and then 4-6 days in G2-3 medium. In the second experiment, oocytes activated by electrical pulse and chemicals were cultured in Barc medium for 7-9 days or 72 h in G1-3 and then 4-6 days in G2-3 medium. In the third experiment, oocytes activated by electrical pulse and chemicals were cultured for 48 h or 72 h in G1-3 and then 5-7 days or 4-6 days in G2-3 medium. The differences among groups were analyzed by one-way ANOVA after arcsin square transformation. In the first experiment, cleavage rate (75.6%), development rate (37.3%), and blastocyst cell number (78.4 � 3.2) of oocytes activated by electrical pulse was higher than for the group without electrical pulse (28.7%, 8.0%, 59.5 � 4.3, respectively; P < 0.05). This result showed that activation was started more effectively by electrical pulse than by chemicals. In the second experiment, there was no significant difference on cleavage rate between the two groups (66.6%, 65.0%, respectively), and the blastocyst development rate of parthenogenetic embryos cultured in G1-3/G2-3 (36.6%) was higher than in the Barc medium group (16.6%; P < 0.05). This result showed that G1-3/G2-3 medium was more effective for parthenogenetic embryo development than Barc medium. In the third experiment, although significant differences could not be found between the two groups in the development rate of parthenogenetic embryos cultured for a total of 7-9 days (30.8%, 39.2%, respectively), the development rate of embryos cultured for 72 h in G1-3 was higher (26.4%) than for the 48-h group (15%; P < 0.05) on Day 7. This result showed that embryos developed more slowly when cultured for a shorter time in G1-3 medium before transfer to G2-3 medium. This study was supported by a grant from TUBITAK, Turkey (VHAG-1022).

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