• Korean Journal of Veterinary Research
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• 제30권2호
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• pp.123-127
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• 1990

By nuclear transplantation technology twenty eight mice have been produced after transfer of heterozygous biparental eggs. Also heterozygous gynogenetic eggs with two female pronuclei and heterozygous androgenetic eggs with two male pronuclei have been obtained by injecting a male or female pronucleus with Sendai virus into the perivitelline space of enucleated haploid zygotes at pronuclear stage. The success rate of enucleation, karyoplast injection and fusion of both the pronuclei was 80.3, 83.4 and 81.8%, respectively. The overall pronuclei fusion rates by this technique were 56, 50 and 56% in biparental, gynogenetic and androgenetic eggs, respectively. The evidence was ascertained that the gynogenetic and androgenetic eggs were also able to develop in vitro up to blastocyst stage, even though their developmental potential was greatly diminished beyond 2-cell stage. The gynogenetic eggs were able to develop in vivo up to day 10 of pregnancy, while the androgenetic eggs failed to develop in vivo during the same period.

• Reproductive and Developmental Biology
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• 제33권2호
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• pp.113-117
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• 2009

Animals produced by somatic cell nuclear transfer (SCNT) using genetically modified cells are almost always transgenic, implying that this method is more efficient than the traditional pronuclear microinjection method. Most somatic cells for SCNT in animals are fetus-derived primary cells and successful gene integration in somatic cells will depend on transfection condition. The objective of this study is to evaluate the efficiency of electroporation (Microporator) and liposome reagents (F-6, F-HD, W-EX, W-Q, W-M) for tissue-type plasminogen activator (tPA) gene transfection and to estimate the overall efficiency of transfection of Korean native pig fetal fibroblast cells (KNPFF). Electroporation showed significantly higher transfection efficiency than liposome reagents with regard to the transfection of in vitro cultures in the early stages of development (41.7% with Microporator vs. 18.3% with F-6, 20.0% with F-HD 18.5% with W-EX, 5.0% with W-M and 6.3% W-Q,). Colonies identified as tPA-positives were treated once more with G418 for 10 to 14 days and growing colonies were selected again. When the cells of newly selected colonies were subjected to single-cell PCR, reselection of colonies following second round of G418 selection increased the rate of transgene integration per each colony. These results suggest that transfection with electroporation is the most efficient and the second rounds of G418 selection may be an effective method for transfection of porcine fetal fibroblast cells.

• Asian-Australasian Journal of Animal Sciences
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• 제17권2호
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• pp.174-178
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• 2004

The objectives of this study were to investigate the ovarian responsiveness of juvenile calves to exogenous gonadotropin treatments and to establish the oocyte retrieval technique for prepubertal heifers. Three 78-day-old calves were treated with 4 doses (40, 30, 30 and 30 mg) of FSH (Folltropin V) at 12 h interval up to 229 day-old. Surgical oocyte retrieval was performed 24 h after the last injection of FSH. Calves with good ovarian responses to FSH treatment had an average ovarian size of $5{\times}3$ cm compared to $3{\times}2$ cm in the less-responsive animals. Large variations were observed in the number of total follicles ($51{\pm}45$), aspirated follicles ($39{\pm}36$), oocytes recovered ($23{\pm}25$) and usable oocytes recovered ($11{\pm}19$) during 78 to 229 day-old. Oocytes derived from prepubertal calves had significantly lower maturation rate than those from cows (34 vs. 100%, p<0.05). Mean diameters of calf oocytes ($144{\pm}1{\mu}m$) and ooplasm ($110{\pm}1 {\mu}m$) were significantly lower than those of cows ($149{\pm}1$ and $25{\pm}1{\mu}m$, respectively). The diameter of the ooplasm also increased significantly after in vitro maturation (IVM) ($108{\pm}1$ vs. $112{\pm}1{\mu}m$). However, further studies are required to optimize the IVP system for the oocytes derived from prepubertal heifers.

• Korean Journal of Animal Reproduction
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• 제24권1호
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• pp.97-108
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• 2000

The objectives of this study were performed to increase the efficiency of the culture conditions of embryos produced in vitro, and to assess the developmental potential after transfer of those embryos into recipients. The mean number of folliclular oocytes recovered from an ovary was 10.7. The rates of maturation and fertilization in Grade I oocytes were significantly (P＜0.05) higher than Graden and III. Developmental rate into blastocyst in the culture group of TCM-199 with BOEC were significantly higher (P＜0.05) than the groups of TCM-199 and conditioned medium (24.7% vs. 12.4% and 18.2%). The survivability of post-thawed blastocysts equilibrated for 3 min in EFS solution was significantly (P＜0.05) lower than l0 for 1 and 2 min (32.1% vs. 82.9% and 73.3%). Significantly higher (P＜0.05) survival rate in blastocysts was seen after freezing than in morulae stage embryos. Out of all 105 recipients, 49 (46.7%) were confirmed in pregnant. On pregnancy of cattle, 48 calves were born from 40 recipients. The ratio of twin and single calves was 30.5% (32/40 and 7.6% (8/40), respectively. However, the others composed of abnormal, as judging as 6 (12.2%) for abortion and 3 (6.1%) for stillbirth during the pregnant period.

• Clinical and Experimental Reproductive Medicine
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• 제24권2호
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• pp.233-239
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• 1997

Embryos of most mammalian species grown in vitro would undergo developmental arrest at the approximate time of genomic activation. Stage-specific cell block and the resulting rapid loss of embryo viability in conventional culture media have limited the duration for which embryos may be cultured prior to transfer. As a result, embryos are usually transferred to the uterus at the 4-to 8-cell stage to avoid the loss of viability associated with long-term in vitro culture. Early transfer has led to asynchrony of the endometrium-trophectoderm interaction at the time of implantation and a resultant reduction in the rate of implantation. To overcome these problems, a variety of co-culture systems has been devised in which embryos can develop for a longer period prior to embryo transfer. Vero cells, derived from African green monkey kidney, share a common embryologic origin with cells from the genital tract. In addition, they are potentially safe to use, since they are highly controlled for viruses and other contaminants. Therefore, co-culture using Vero cells has been widely utilized to enhance embryo viability and development, although not without controversies. We thus designed a series of experiments to demonstrate whether Vero cells do indeed enhance mouse embryo development as well as to compare the efficacy of co-culturing mouse 1-cell embryos on Vero cell monolayer in both Ham's F-10 and human tubal fluid (HTF) culture media. 1-cell stage ICR mouse embryos were cultured either in the presence of Vero cells (Group A) or in conventional culture medium alone (Group B). In Ham's F-10 significantly more 3-to-8cell embryos developed in group A than group B (59.8 versus 10.0%; p<0.01). In contrast, there was no significant difference in embryonic development both group A and group B in HTF. However, significant differences were noted only in later embryonic stage (13 and 0%; p<0.05 of group A and B respectively, hatching or hatched). In Ham's F-10, we also could observe the beneficial effect of Vero cell on hatching process (70.7 and 42.1%; p<0.05 of group A and group B respectively).

• Journal of Embryo Transfer
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• 제22권3호
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• pp.155-160
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• 2007

During in vitro culture of mammalian oocytes and embryos, the cells are exposed to the risks that cause cell injury or death. Numerous studies have been reported that the cell injury may be induced by the action of free radicals generated by auto-oxidation. This study was undertaken to investigate the optimal culture condition system for in vitro culture of porcine embryos. We first evaluated the effect of culture media on the porcine embryo development. NCSU-23 and PZM-5, culture medium tested, were failed to produce significant difference on the rate of blastocyst formation. In NCSU-23, the developmental rate was slightly higher than that in PZM-5. During in vitro maturation (IVM), fertilizaton (IVF), and culture (IVC) under 5 or 20% oxygen ($O_2$), the rates of cleavage and development were insignificantly different from each other under our culture condition (20% $O_2$, in NCSU-23), the mean cell number per blastocyst was $40{\pm}10$. These results showed that medium and $O_2$ concentration had no significant effect on the development of porcine embryos.

• Reproductive and Developmental Biology
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• 제29권2호
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• pp.127-131
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• 2005

The objective of this study was to examine the effect of EGF on meiotic maturation and pronuclear (PN) formation of porcine oocytes. Prepubertal gilt cumulus-oocyte-complexes (COCs) aspirated from $2\~6mm$ follicles of abbatoir ovaries were matured in TCM199 containing 0.1mg/ml cysteine, $0.5{\mu}/ml$ FSH and LH, and EGF (0, 5, 10, 20, 40 ng/ml) for 22 hr at $39^{\circ}C$ in a humidified atmosphere of $5\%$ $CO_2$ in air. They were then cultured for an additional 22hr without hormones. In Experiment 1, to examine the nuclear maturation at 44hr of culture, the expanded cumulus cells were removed by vortexing for 1 min in 3 mg/ml hyaluronidase. The oocytes were fixed in acetic acid: methanol (1:3, v/v) at least for 48 hr and stained with $1\%$ orcein solution for 5 min. Nuclear status was classified as germinal vesicle (GV), germinal vesicle breakdown (GVBD), prophase-metaphase I (PI-MI), and PII-MII under microscope. In Experiment 2, to investigate PN formation, oocytes were fertilized with Percoll-treated freshly ejaculated sperm $(1\times10^5\; cells/ml)$ in mTBM with $0.3\%$ BSA and 2mM caffeine for 5hr, and cultured in NCSU-23 medium with $0.4\%$ BSA. At 6hr of culture, the embryos were fixed in $3.7\%$ formaldehyde for 48hr and stained with 10ug/ml propidium iodide for 30 min. PN status was classified as no or one PN (unfertilized), 2 PN (normal fertilized) and $\geq3$ PN (polyspermy). Differences between groups were analyzed using one-way ANOVA after arc-sine transformation of the proportional data. The rate of oocytes that had reached to PII-MII were significantly (P<0.05) higher in all groups added EGF than that of non-treated group $(67\%)$, but it did not differ among the all added groups $(86\%,\;85\%,\;79\%\;and\;81\%$, in 5, 10, 20 and 40 ng/ml EGF, respectively). No differences on the incidence of 2PN were observed in all treated groups $(25\%,\;30\%,\;33\%,\;29\%\;and\;29\%$, in 0, 5, 10, 20 and 40 ng/ml EGF, respectively), however, in non-treated group, polyspermy tended to be increased ($66\%\;vs\;. 58\%,\;54\%,\;52\%\;and\;55\%$, 0 vs. 5, 10, 20, 40 ng/ml EGF, respectively). These results suggest that EGF can be effectively used as an additive for enhancing oocyte maturation and reducing the incidence of polyspermy in pig.

• Asian-Australasian Journal of Animal Sciences
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• 제20권3호
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• pp.334-339
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• 2007

Reactive oxygen species (ROS) generate during electrical activation of oocytes which has detrimental effects on embryo survival when overwhelmed. The present study was designed to investigate the ability of L-ascorbic acid, a novel water soluble antioxidant, to reduce the ROS level in developing embryos and their subsequent effects on embryo development in vitro. The compact cumulus oocyte complexes (COCs) were cultured in tissue culture medium (TCM)-199 supplemented with 10 ng/ml epidermal growth factor, 4 IU/ml pregnant mare serum gonadotropin (PMSG), and human chorionic gonadotropin (hCG) and 10% (v/v) porcine follicular fluid (pFF) for 44 h. After maturation culture, the denuded oocytes were activated with a single DC pulse of 2.0 kV/cm in 0.3 M mannitol solution containing 0.5 mM of HEPES, 0.1 mM of $CaCl_2$ and 0.1 mM of $MgCl_2$ for $30{\mu}s$ using a BTX Electro-cell Manipulator. The activated oocytes were cultured in modified North Carolina State University-23 (mNSCU-23) medium for 168 h. The level of $H_2O_2$ in each embryo was measured by the dichlorohydrofluorescein diacetate (DCHFDA) method at 48 h after activation. The blastocyst formation rate was significantly higher when culture medium was supplemented with 50 and $100{\mu}M$ L-ascorbic acid (31.2 and 38.7%, respectively) compared to non-supplemented (16.1%) group. Accordingly, significantly more cells in blastocyst were found for 50 and $100{\mu}M$ L-ascorbic acid (50.0 and 56.4, respectively) compared to 0 and $200{\mu}M$ L-ascorbic acid (36.5 and 39.8, respectively). L-ascorbic acid reduces the $H_2O_2$ level in developing embryos in a dose-dependant manner. The $H_2O_2$ level (pixels/ embryos) was 191.5, 141.0, 124.0 and 163.3 for 0, 50, 100 and $200{\mu}M$ L-ascorbic acid, respectively. So, we recommend to supplement 50 or $100{\mu}M$ L-ascorbic acid in porcine in vitro culture medium.

• Development and Reproduction
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• 제12권1호
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• pp.67-76
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• 2008

Oxidative damage resulted from reactive oxygen species (ROS) is one of the main causes for the decrease of the viability during in vitro culture and cryopreservation process. This experiment was performed to determine the effects of antioxidants on the human hematopoietic stem cell (HSC) during cryopreservation procedure. HSCs cultured in vitro with or without antioxidants were frozen and then examined for stem cell potential after thawing. The cell viability of thawed HSC was increased in $\alpha$-tocopherol and ascorbic acid treatment group compared to control group ($62.7{\pm}8.0%$) and it was higher in 150 uM $\alpha$-tocopherol treatment group ($70.5{\pm}7.0%$). No significant difference was observed in the membrane integrity in all groups. In auto-differentiation rate, no significant difference was appeared in all groups, but was lower in 150 uM $\alpha$-tocopherol ($7.3{\pm}2.6%$) compared to control group ($10.1{\pm}1.6%$). These results demonstrate that treatment of antioxidants improves the efficiency of cryopreservation for HSC and $\alpha$-tocopherol may be considered effective antioxidant for the protective effect on HSC.

• Development and Reproduction
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• 제10권4호
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• pp.239-245
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• 2006

Experiments were conducted to determine the effects of beta-mercaptoethanol(${\beta}-ME$) supplements to the maturation medium on in vitro fertilization(IVF) and intracellular glutathione(GSH) concentration. Bovine cumulus-intact oocytes were matured in TCM-199 medium containing FBS, hormonal supplements, and ${\beta}-ME$(0, 25 and $50\;{\mu}M$) for 12h and 24 h. After culture, cumulus-free matured oocytes were co-incubated with frozen-thawed spermatozoa for 24h. Maturation rate increased(p<0.05) in ${\beta}-ME$ treatment group, but no significant differences among treatment groups. Also, increases(p<0.05) in intracellular GSH concentration before and after fertilization were observed in $50\;{\mu}M\;{\beta}-ME$ supplements to the maturation medium. Male pronuclear formations after IVF was increased(p<0.05) in ${\beta}-ME$ treatment group, but no significant difference among treatment groups. In conclusion, supplementing ${\beta}-ME$ into the maturation medium increased maturation rates, fertilization rates, and intracellular GSH concentrations.