• Journal of Embryo Transfer
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• v.26 no.4
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• pp.251-256
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• 2011

Presently, the effect of 0.5 mM dibutyryl cAMP (dbcAMP)-supplemented maturation medium during different incubation time on meiotic arrest (germinal vesicle) and resumption (metaphase II) of porcine oocytes and embryonic development of porcine oocytes following in vitro fertilization (IVF) or parthenogenetic activation (PA) was determined. Porcine cumulus oocyte complexes (COCs) were cultured in 0.5 mM dbcAMP for 17, 22, 27, or 42 h, and an additional 22 h without 0.5 mM dbcAMP. The nuclear status was examined at each time point. Oocytes cultured from 39~49 h displayed more than 80% meiotic resumption. More than 85 % of meiotic arrest was presented at 17~22 h. Oocytes were cultured for 22 h with 0.5 mM dbcAMP and additional 22 h without dbcAMP to assess developmental potential following IVF or PA. There were no significant differences in blastocyst rates among the dbcAMPIVF, IVF, dbcAMP-PA, and PA groups, although cleavage rate of IVF group was significantly higher than those of dbcAMP-PA, and PA groups. In conclusion, 0.5 mM dbcAMP influenced meiotic maturation of porcine oocytes depending on incubation time of oocyte, although embryonic development was not improved in both IVF and PA.

• Animal Bioscience
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• v.36 no.5
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• pp.710-719
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• 2023

Objective: The present study investigated whether protodioscin (PD), a steroidal saponin mainly found in rhizome of Dioscorea species, alleviates oxidative stress-induced damage of porcine oocytes during in vitro maturation. Methods: Oocytes were treated with different concentrations of PD (0, 1, 10, 100, and 200 µM) in the presence of 200 µM H₂O₂ during in vitro maturation. Following maturation, spindle morphology and mitogen-activated protein kinase activity was assessed along with reactive oxygen species level, GSH activity, and mRNA expression of endogenous antioxidant genes at the MII stage. On the day 7 after parthenogenetic activation, blastocyst formation rate was calculated and the quality of embryo and mRNA expression of development-related genes was evaluated. Results: Developmental competence was significantly poorer in the 0 µM PD-treated (control) group than in the non-treated (normal) and 10 µM PD-treated (10PD) groups. Although the reactive oxygen species level did not significantly differ between these three groups, the glutathione level and mRNA expression of antioxidant genes (superoxide dismutase 1 [SOD1], SOD2, nuclear factor erythroid 2-related factor 2 [Nrf2], and hemo oxygenase-1 [HO-1]) were significantly higher in the normal and 10PD groups than in the control group. In addition, the percentage of oocytes with defective spindle and abnormal chromosomal alignment was significantly lower and the ratio of phosphorylated p44/42 to total p44/42 was significantly higher in the normal and 10PD groups than in the control group. The total cell number per blastocyst was significantly higher in the 10PD group than in the control group. The percentage of apoptotic cells in blastocysts was highest in the control group; however, the difference was not significant. mRNA expression of development-related genes (POU domain, class 5, transcription factor 1 [POU5F1], caudal type homeobox 2 [CDX2], Nanog homeobox [NANOG]) was consistently increased by addition of PD. Conclusion: The PD effectively improves the developmental competence and quality of blastocysts by protecting porcine oocytes against oxidative stress.

• Korean Journal of Animal Reproduction
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• v.26 no.2
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• pp.173-182
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• 2002

The mechanisms underlying of the visual assessment and resulting in optimum embryonic development following in vitro maturation, fertilization, and culture are unclear, It was known that in vitro produced embryos show more frequent occurrence of fragmentation, which resulted in poor developmental potential and decreased implantation rate. The objective of this study was to investigate the apoptotic rates in bovine blastocyst derived from in vitro fertilization (IVF) and nuclear transfer (NT). In addition, the expression levels of Bcl-2 and Bax gene were investigated in the blastocyst to confirm their potential roles in the regulation of apoptosis during preimplantation embryonic development. Analysis of apoptosis was carried out by using terminal deoxynucleotidyl transferase mediate dUTP nick end labeling (TUNEL) method. The levels of Bcl-2 and Bax gene in the blastocyst derived from IVF and NT were determined by RT-PCR. The proportion of TUNEL positive signal in blastocyst derived from NT was significantly higher than that in blastocyst derived from IVF (p<0.001). Bcl-2 expression level of blastocyst derived from IVF was higher than that of blstocyst derived from NT. However, high expression level of Bax was observed in the blastocyst derived from NT. These results indicates that apoptosis is more responsible for fiagmentation in bovine blastocyst derived from NT than IVF. These results suggested that the increase of developmental failure followed by NT could be caused by nuclear fragmentation as apoptosis.

• Journal of Embryo Transfer
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• v.25 no.4
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• pp.259-262
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• 2010

Optimization of the preimplantation mammalian embryo culture condition was widely focused on refining medium composition under the name of chemically defined media. However, recent research revealed that the alteration of physical environment can be a crucial factor to a successful embryo development. In this study, under the same embryo density, a novel culture device named oil-free micro tube culture (MTC) system was evaluated using porcine parthenogenetic embryos. The activated oocytes were placed into the 0.2 ml thin-wall flat cap PCR tube and cultured to the blastocyst stage. As a preliminary step, embryo density and culture medium volume were optimized under a standard drop culture system. The optimal embryo density range for in vitro culture was 0.5 embryos per ${\mu}l$ in $20\;{\mu}l$ drop (20.5%) and 1.0 embryos per ${\mu}l$ in $10\;{\mu}l$ drop (20.6%). Based on these results, we compared drop culture system and 'MTC' system in terms of the developmental rate to the blastocyst stage. In $20\;{\mu}l$ medium volume, the 'MTC' system showed similar blastocyst formation rate when compared with drop culture system (20.2% versus 20.5%, respectively) while the 'MTC' system showed lower blastocyst formation rate than drop culture system in $10\;{\mu}l$ one (12.7% versus 20.0%, respectively). Therefore the $20\;{\mu}l$ MTC system may be an alternative incubation system for short-distance embryo transport without carrying the $CO_2$ incubator and this provides novel embryo culture device to clinical veterinary embryologists.

• Reproductive and Developmental Biology
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• v.31 no.4
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• pp.235-240
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• 2007

This study was conducted to examine the viability of Korean native striped cattle (Bos namadicus Falconer, Chikso) clone embryos after embryo transfer. Chikso somatic cell nuclear transfer (SCNT) embryos were produced by fusion of ear skin cells derived from a female Chikso with enucleated oocytes matured in vitro for 18-24 hr. After in vitro culture of SCNT embryos for 7 to 8 days, fresh or vitrified blastocysts derived from SCNT were transferred into a uterine horn of recipient cows. Fifteen of total 43 recipients were pregnant at Day 50 and 4 recipients were maintained to term. Three IVF-derived calves and 1 clone Chikso calf were born. Pregnancy rate was higher when fresh embryos were transferred to recipients compared to vitrified embryos, but development to term was not different between both groups. The clone Chikso calf died at 5 days after birth due to the fullness of amniotic fluid in rumen and the infection of umbilical cord. The result of the present study shows that clone Chikso calf can produced from the embryo transfer of SCNT embryos, however, solution of abortion problem is necessary to improve the cloning efficiency.

• Reproductive and Developmental Biology
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• v.29 no.3
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• pp.181-186
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• 2005

This experiment was conducted to investigate effects of the two different in vitro production systems, serumcontaining system (IVM, IVF and IVC; TCM199, TALP and CR1aa) and serum-free system (IVM, IVF and IVC; IVMD101, IVMD100 and IVMD101), on the development of in vitro fertilized or DNA-microiniected embryos. We also examined the effect of DNA dosage and its expression pattern in embryos. The DNA used for microinjection was a green fluorescence protein gene. The development rates to $\geq$ 2cell, 8cell and blastocyst stage were significantly higher in vitro fertilized embryos than those in DNA-microinjected embryos. The development rate to the 8-cell stage was significantly higher in serum-free system than in serum-containing system (p<0.05; $3.3\%\;vs.\;15.5\%\;and\;21.4\%$, respectively). The development rates to the blastocyst stage of in vitro fertilzed or DNA-microinjected embryos between two different culture system ($2.7\%\;vs.\;2.3\%\;and\;23.0\%\;vs.\;23.6\%$, respectively) were not different. The development rates of embryos injected 2 ng/uL DNA was higher. than those of embryos injected 4 or 8 ng/uL DNA. The GFP expression rate of 1-cell embryos was significantly higher than that of 2-cell and 4-cell embryos, whereas the rates were not different between 4-cell and blastocyst-stage embryos.

• Development and Reproduction
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• v.10 no.2
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• pp.115-125
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• 2006

The present experiment was performed to confirm the effects of selenium on maturation and viability of mouse oocyte. Maturation of oocytes was observed by microscope, Germinal vesicle breakdown(GVBD) and polar body formation(PB) were confirmed at 2.5, 13 hours after in vitro culture. Viability of oocytes was observed by microscope. Normal and abnormal oocytes were distinguished by morphological change in vitro culture for 72 hours. Glutathione(GSH) content of collected oocytes from individual stage also was measured by glutathione assay using spectrophotometer. The results obtained were as follows; The low concentration of selenium($0.005\;{\mu}g/mL{\sim}0.5\;{\mu}g/mL$) increased the maturation rate of germinal vesicle(GV) oocytes to GVBD and PB oocytes. The high concentration of selenium($5\;{\mu}g/mL$) decreased the maturation rate. The low concentration of selenium increased the viability rate of PB oocytes. The high concentration of selenium did not affect the viability rate. The low concentration of selenium increased the GSH content in PB oocytes. The high concentration of selenium decreased GSH content. GSH content in PB oocyte was much higher than that in GVBD oocyte. The results indicate that the low concentration of selenium increases the maturation rate by helping quality elevation of oocyte and minimizing damages of oxidative stress generated from metabolism process. The low concentration of selenium also increases the viability rate by increasing GSH content.

• Journal of Embryo Transfer
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• v.20 no.2
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• pp.123-128
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• 2005

This study examines the effects of kinds and concentrations of cryoprotectants on the survival rate of vitrification-thawed porcine oocytes, together with the effects on survival, in vitro fertilization and development of immature oocytes. 1. The developmental rate of oocytes to MII and diploid stage when the vitrification-thawed of recovered immature oocytes cultured for 0, 15, 30 and 40h were cultured for 0, 15, 30 and 40h were $56.7\%,\;53.3\%,\;63.3\%,\;65.0\%\;and\;23.3\%,\;18.3\%,\;10.0\%,\; 3.3\%$, respectively. The in vitro development to MII stage were lower than the control group $(78.2\%)$, but higher fo. diploid stage $(5.5\%)$. 2. When the vitrification of immature oocytes after being culture for 0, 15, 30 and 40 hours, the survival rate were $34.0\%,\;26.0\%,\;18.0\%\;and\;10.0\%$ respectively. This result was lower than that of the control group $(60.0\%)$. 3. When the fertilization of the vitrified immature oocytes after being culture for 0, 15, 30 and 40 hours, the in vitro fertilization rate were $60.0\%,\;54.0\%,\;48.0\%,\;38.0\%$, and developmental rates were $26.0\%,\;18.0\%,\;8.0\%,\;4.0\%$, respectively. This results were lower than the control group $(78.0\%\;and\;38.0\%)$. 4. When the fertilization of the immature oocytes after being culture for $0\~15$ hours vitrified with EDS and ETS, the fertilization and developmental rates were $50.0\%,\; 22.0\%$ and $46.0\%,\;18.0\%$, respectively. This results were lower than the control group $(74.0\%\;and\;38.0\%)$.

• Reproductive and Developmental Biology
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• v.28 no.1
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• pp.29-36
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• 2004

The objective of this study was to investigate the effects of amino acid supplementation of oocyte maturation medium on 1st polar body(PB) extrusion, embryo development and blastocsyt cell number. In experiment 1, Cumulus oocyte complexes(COCs) were matured in in vitro maturation(IVM) medium supplemented with 1, 2, or 4-fold of 10 $\mu$l/ml MEM non-essential amino acid(NEAA) and 20 Park, $\mu$ l/ml BME essential amino acid(EAA). The PB extrusion rate of oocytes matured in 1-fold amino acid group was significantly higher than that matured in medium without amino acid (p＜0.05), but it was decreased by the increase of the dosage of amino acid. There were no difference in the percentage of embryos reaching 2-cell, 8-cell and blastocyst in all treatments. The number of trophectoderm(TE) cells and total cell number of blastocysts were highest in 2-fold amino acid group, and the number of inner cell mass(ICM) cells was increased by the increase of the dosage of amino acid. In experiment 2, COCs were matured in IVM medium with 1, 5, or 10 mg/ml lactalbumin hydrolysate(LAH). The PB extrusion rate of oocytes matured in medium with 5 mg LAH was significantly higher than that matured in medium with 1 mg LAH (p＜0.05). The development rate to the blastocyst stage was significantly higher in non-supplement and 1 mg LAH group than in 5 mg and 10 mg LAH group (p＜0.05). The number of TE cells and total cell number did not differ among treatment groups, but the number of ICM cells was increased by the increase of LAH supplement. These results suggested that the supplement of certain group of amino acid in IVM medium effective on the quality of blastocyst, and further studies will be accompany with the search of new sources of amino acid used for the use of in vitro embryo production.

• Clinical and Experimental Reproductive Medicine
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• v.31 no.3
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• pp.169-176
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• 2004

Objective: This study was performed to evaluate and compare the embryonic developmental capacity and pregnancy rates in conventional in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) with ejaculated sperm or testicular sperm cycles. Materials and Methods: Fertilization was examined in the following morning after IVF (group I), ICSI (group II) or TESE-ICSI cycles (group III). Fertilized oocytes were co-cultured with Vero cells until embryo transfer (ET). On day 2 and $5{\sim}7$, grades of embryos (<4- or $\geq$4-cell) and blastocysts (BG1, 2, 3 or early) were evaluated. Clinical pregnancy rate was determined by detecting G-sac with transvaginal ultrasonogram. We analyzed the results by $X^2$ and Student's t-test and considered statistically significant when P value was less than 0.05. Results: Fertilization rate was significantly higher (p<0.05) in group I ($79.0{\pm}21.2%$) than in group II and III ($56.8{\pm}21.6%$ and $36.7{\pm}25.3%$). Cleavage and blastulation rate of group I ($95.8{\pm}13.8%$ and $59.5{\pm}25.3%$) were significantly higher (p<0.05) than those of group III ($83.4{\pm}18.6%$ and $40.4{\pm}36.5%$). Clinical pregnancy rate was significantly higher (p<0.05) in group I and II (40.7% and 41.7%) than that in group III (12.5%). No differences were found in the rates of multiple pregnancy and abortion among three groups. Embryonic implantation rate was higher in group I ($15.1{\pm}20.2%$, p<0.05) and II ($14.7{\pm}20.6%$, NS) than that in group III ($5.1{\pm}15.6%$). However, embryonic implantation rate was increased in ET with blastocyst(s) among three groups. Conclusions: Fertilized oocytes obtained from TESE-ICSI were harder to be successfully cultured to blastocyst stage for 5$\sim$7 days than that from IVF cycles. However, all blastocyst(s) ET increased the embryonic implantation rate equally in IVF, ICSI and TESE-ICSI cycles.