• Korean Journal of Animal Reproduction
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• v.24 no.4
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• pp.407-417
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• 2000

The present study was to examine effects of various electrical stimulus treatments used for electro-fusion on the preimplantation development of bovine nuclear transfer (NT) embryos with fetal fibroblast cells. Fetal fibroblast cells were isolated from one fetus at day 45 of gestation in Holstein cow, and passaged 3 to 4 times before being transferred into enucleated oocytes. Single fibroblast cells were individually placed into the perivitelline space of enucleated oocytes by using a micromanipulator. At first, the fusion and developmental rates of reconstructed oocytes were compared between different electric stimulation conditions. When fusion of the reconstructed oocyte was induced by different electric pulse periods (15, 30 and 45 $\mu$sec) at a DC pulse of 1.8 kV/cm, 15 (45.5%, 120/264) or 30 $\mu$ sec group (43.9%, 106/241) showed a higher fusion rate than 45 $\mu$sec group (23.2%, 58/250, P＜0.05). However, no difference was detected in the development rate of the fused oocytes to blastocysts between groups. Next experiment was to examine the effects of different electrical field strengths (1.5, 1.8 and 2.1 kV/cm) for 15 $\mu$sec at electrofusion on in vitro development of the NT embryos. As results, there was no difference in the fusion and developmental rates of the NT embryos between electrical strength (P＞0.05). Finally, developmental competence of bovine NT embryos with somatic cells was compared with IVF-derived embryos. Of enucleated oocytes fused with fibroblast cells, 27.4% (75/274) developed to the blastocyst stage, which is similar to that (24.5%, 58/237) of IVF-derived embryos. However, mean nuclei number of NT blastocysts was smaller than that of IVF-derived blastocysts. Thus, we have established an optimal condition (1.8 kV/cm, 15 $\mu$sec) for electric fusion of bovine NT oocytes with somatic cells. The present study indicates that bovine reconstructed embryos with somatic cells normally develop to blastocyst stage in vitro, although having smaller nuclei numbers of blastocysts as compared to IVF-derived embryos.

• Journal of Life Science
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• v.6 no.3
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• pp.204-212
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• 1996

The aim of this study was to evaluate the effects of phosphate, aimno acid, and BSA on in vitro development of mammalian embryos. In vitro-matured and -fertilized(IVM/IVF) bovine embryos were cultured in simple, chemically defined, protein-free medium(mTLP-PVA0. When the phosphate concentration of mTLP-PVA supplemented with 19 amino acid were adjusted to 0.0, 0.10, 0.35, 1.05 and 2.10mM by the concentration of sodium phoshpate, there were no significant different in development ability of IVM/IVF bovine embryos cultured in the medium containing from 0.00 to 1.05mM phosphate until 48 hours post-insemination, However, proportion of embryos developing to $$8-cell and morula at 96 and 144 hours post- insemination, respectively, was significantly increased in the medium with o.35 mM phosphate(p<0.05). There was significant difference between O.10(18%)-0.35(24%)mM phosphate and 1.05(13%)-2.10(1%)mM phosphate in supporting development to blastocyst(p<0.05). When IVM/IVF bovine embryos were cultured in the medium supplemented with 19 amino acids, significant different was observed in the proporton of embryos reaching $$8-cell(49-50%), morula(38-40%) and blastocyst (29-32%) stages at 96, 144, and 192 hours post-insemination, respectively(p<0.05). Glutamine alone had no benefit on embryo development. When BSA was added to mTLP-PVA with 0.35mM phosphate, glutamine and 19 amino acids at 8, 48, 120 hours post-insemination, BSA significantly enhanced the development ability ofb embryos reaching $$2-cell (74-77%), $$8-cell (49-53%), morula(43-47%), and blastocyst(38-42%) stages at 48, 96, 144, and 192 hours post-insemination, respectively, regardless of the time of BSA addition.

• Korean Journal of Animal Reproduction
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• v.17 no.4
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• pp.287-294
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• 1994

This study was to investigate the effects of electrofusion, activation and developmental stage of donor embryos on in vitro development of nuclear transplant bovine embryos. A single blastomere nucleus from 8-cell to morula stage embryos produced by in vitro fertilization(IVF) was transferred into a recipient oocyte enucleated at 23∼25 h after in vitro maturation(IVM) or into a recipient oocyte enucleated and cultured for 14∼15 h. In one experiment the nuclear transplant embryos were subjected to additional activation treatments. Fusion rate of nuclear transplant eggs was high at direct current(D.C) voltages of 1.0 and 1.5 kV/cm 991.5 and 93.3%, respectively), but decreased at 2.0kV/cm (81.8%). Additional activation treatments by electric pulases or 7% ethanol did not affect the cleavage and development of nuclear transplant embryos. Development of nuclear transplant embryos slightly increased by delayed nuclear transfer and fusion (42∼43 h after IVM). With this system, blastocysts were obtained from transfer of 8-cell to morula stage donor nuclei (9.6%∼2.4%). The result of this study suggests that nucleo-cytoplasmic interactins, expecially activation of ooplast are very important for the development of nuclear transplant embryos, and donor cell stage does not affect the development of nuclear transplant embryos.

• Journal of Embryo Transfer
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• v.9 no.3
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• pp.261-268
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• 1994

Immatured bovine follicular oocytes added with serum, hormones, granulosa cells and bovine oviduct epithelium cells were fertilized in vitro after in vitro maturation. In vitro maturation and early development capacity were examined and IVF-derived embryos were transferred and to recipients and effects of sperm treatment on in vitro capacitation were investigated. The rate of in vitro maturation was improved when they were co-culutred with granulosa cells in the TCM199 medium added with 10% FCS and hormones. The percentage of acrosome reaction was not differed between sperm treatments and sperm of above 25% under-went AR during 30 min preincubation with caffeine and heparin. The cleavage rate of oocytes in vitro fertilized in TCM199 medium added with 10% FCS and hormones, GC or BOEG higher than that in medium with 10% FCS and GC. But the rate was not significantly different between GC and BOEG The cleavage of rate oocytes cultured in medium containing serum, hormones and BOEG was 80.2% and more embryos were developed to Blastocyst (17.3%). The selected embryos were transferred to 9 recipients by surgical or nonsurgical method but did not result in pregnancy.

• Journal of Embryo Transfer
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• v.10 no.3
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• pp.229-236
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• 1995

The experiments reported here take advantage of the large number of in vitro matured and in vitro fertilized(IVM /IVF) bovine oocytes which can be produced, permitting the design of controlled experiments to establish a simple defined medium for the study of early embryo requirements. A total of 1,386 IVM /IVF oocytes were used to compare a simple defined medium(KSOM) with more complex culture conditions used successfully for culture of bovine embryos but do not permit study of specific requirements. All experiments were extensively replicated factorials. In Experiment 1, KSOM was superior to Menezo B$_2$ medium in producing morulae plus blastocysts from IVM /IVF oocytes(33 vs 20%, P<0.()5). The yield of morulae plus blastocysts with KSOM was 22% and with BRLC added was 30%. In Experiment 2, (a 2x2 factorial of KSOM with or without BRLC and 0, 1 ng /ml of platelet derived growth factor, PDGF) more morulae plus blastocysts (40%) were produced in KSOM-BRLC co-culture containing 1 ng /ml PDGF than in the control KSOM(12%). In Experiment 3, there was no dose response when 0, 1 and 5 ng /ml of PDGF were added. The results with simple defined KSOM medium are sufficiently promising to indicate that specific requirements of the embryo may be examined in future studies with KSOM as a base.

• 대한생식의학회:학술대회논문집
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• 1995.12a
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• pp.43-45
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• 1995

• Journal of Embryo Transfer
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• v.10 no.1
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• pp.53-63
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• 1995

The effects of different protein sources (serum vs bovine serum albumin), growth factors (EGF and PDGF) and co-culture with various type of somatic cel1s (BOEC, MEF and BRL) on the in vitro development of in vitro matured / in vitro fertilized bovine oocytes were examined, and the viability of frozen/thawed embryos derived from IVM /IVF was examined. Cell numbers of blastocysts were also counted. In Experiment 1, CR$_1$aa with serum was superior to CR$_1$aa with BSA in producing morulae plus blastocysts from IVM /IVF oocytes(24.4% vs 30.4%, p>0.05). In Experiment 2, more morulae plus blastocysts(42.3%) were produced in CR$_1$aa containing long /ml EGF than in the control CR$_1$aa(33.3%). In Experiment 3, 2- to 8-cell embryos derived from IVM /IVF oocytes were randomly allotted to one of 4 culture groups : a) CR$_1$aa ; b) CR$_1$aa + ing /ml PDGF ; CR$_1$aa + Sng /ml PDGF ; CR$_1$aa + lOng /ml PDGF ; culture resulted in 21.3, 51.2, 41.4 and 45.9%(p<0.05), respectively, developing into morulae and blastocysts. In Experiment 4, 0 and Sng /ml PDGF added to CR$_1$aa coculture with BRL or BOEC yielded 47.5, 42.5, 33.8 and 41.6% morulae and blastocysts, respectively. In Experiment 5, the proportion of embryos into morulae and blastocysts was highest in CR$_1$aa with MEF coculture group(50.9%) compared to any other group(CR$_1$aa, 22.3%; CR$_1$aa+BRL, 32.9%; CR$_1$aa+BOEC, 33.8%, p>0.05). In Experiment 6, survival rate of blastocysts produced by in vitro fertilization when cryoprotectant was removed in 0.7M glycerol+0.7M sucrose and 0.7M sucrose solution for 10 min. after thawing at 2$0^{\circ}C$ (Exp. H, 58.8%) was slightly higher than when cryoprotectant was removed 10%, 6.7% and 3.3% glycerol for 10 min. after thawing at 37$^{\circ}C$ (Exp. I, 54.3%). These study indicate that growth factors and somatic cell co-culture can increase the proportion of embryos that develop into morulae and blastocysts without an increase in the cell number and frozen /thawed method employed this experiment was not different.

• Korean Journal of Animal Reproduction
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• v.18 no.1
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• pp.47-54
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• 1994

The objective of this study was to produce Korean native calves following transfer of in vitro matured, fertilized and cultured embryos into Holstein cows. The ovaries of Korean native cows or heifers were obtained from an abattoir and kept on 25 to 28$^{\circ}C$ and transported to laboratory within 2 hrs. The oocytes were matured in vitro (IVM) for 24 hrs in TCM-199 supplemented with 35$\mu\textrm{g}$/ml FSH, 10$\mu\textrm{g}$/ml LH, 1$\mu\textrm{g}$/ml estradiol-17$\beta$ and granulosa cells at 39$^{\circ}C$ under 5% CO2 in air. They were fertilized in vitro (IVF) by epididymal spermatozoa treated with heparin for 24 hrs., and then the zygotes were co-cultured in vitro (IVC) with bovine oviductal epithelial cells for 7 to 9 days. Late morulae and blastocysts produced in vitro were nonsurgically transferred to recipient cows by unilaterial. Recipients were monitored for estrus and for pegnancy by rectal plapation in 60 days after embryo transfer. One of them was pregnant to term and produced a female weighing 42.5kg at birth.

• Korean Journal of Animal Reproduction
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• v.18 no.2
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• pp.121-126
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• 1994

This study was conducted to examine the condition of activation of the nuclear transplant bovine embryos. In vitro fertilized(IVF) and nuclear transplant embryos(NTs) were co-cultured with bovine oviduct epithelial tissue(BOET). NTs were treated with cycloheximide(CHXM) for 0 to 6 h after electrofusion to investigate the activation conditin of recipient ooplast. Then, the infljence of the CHXM treatment timing on the cleavage and development of NTs were investigated in relation to the nuclear transplant time. The cleavage rates of NTs were increased with the increasing time of the CHXM treatment from 0 to 6 h (54.7 to 91.3%, P<0.01). Similar trend was shown in the development into the morula or blastocyst stage, but very limitted. Activation of enucleated oocytes prior to fusion enhanced development of NTs compared with that post fustion. This result suggests that the frequency of activation of NTs can be greatly enhanced by treating with CHXM for 6 h. The result also suggests that if blastomeres of unknown cell cycle stage are used, activation of enucleated oocytes prior to fusion enhances development of NTs.

• Proceedings of the KSAR Conference
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• 2001.03a
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• pp.40-40
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• 2001

Heat stress to bovine oocytes and embryos has suggested a potential role of retardation of their development. Limited study has reported on the effect of heat shock on sperm before using it for IVF. Caudal epididymal sperm cultured in 42$^{\circ}C$ incubator for 0.5, 1 and 2 h compared on sperm viability and oocyte development after its use for IVF to those of control. Oocytes were matured for 22 h and then inseminated with treated or control sperm for 16 h. Embryos were cultured in CRlaa medium, transferred to TCM199＋10% FBS on day 4, and maintained on day 9. A higher proportion (84.1%, 0.5 h; 72%, 1 h: 65%, 2 h) in treated sperm was observed dead and abnormal pattern as 100% of consider as control. In control the rates of cleavage and development into blastocyst were 76% and 22%, respectively, and did not differ the rates between 1 h and 2 h of culture. Significant differences were appeared in the rates between treated for an hour and control (32% and 5% vs. 54% and 10%, respectively). Moreover increased time of culture is more retardation to be cleaved the oocytes. However, the rates of blastocyst from cleaved embryos in treated group similar to control (25% vs. 29%, respectively). The reason for this remains unclear, but male sperm, from preliminary experiment(data un-shown) for sexing of resulting embryos, would be more fragility on heat stress.