• Korean Journal of Animal Reproduction
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• v.21 no.3
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• pp.293-302
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• 1997

Follicular oocytes of Grade I and II were collected from 2~6 mm ovarian follicles and matured in vitro (IVM) for 24 hrs in TCM-199 su, pp.emented with 35$\mu\textrm{g}$/ml FSH, 10$\mu\textrm{g}$/ml LH, and 1$\mu\textrm{g}$/ml estradiol-17$\beta$ at 39$^{\circ}C$ under 5% CO2 in air. They were fretilized in vitro (IVF) by epididymal spermatozoa capacitated with heparin for 12 hrs. The zygotes were then co-cultured in vitro with bovine oviducted epithelial cells (BOEC) for 7 to 9 days. The optimal time for IVM, the successful enucleation of IVM oocytes by micromanipulation at different oocyte ages after IVM, and the ideal culture system for IVM for effective IVF and in vitro development of IVM-IVF embryos was examined for in vitro production of nuclear recipient oocytes and nuclear donor embryos. To improve the efficiency of nuclear transplantation (NT) of IVF embryo into IVM follicular oocytes, this study evaluated the optimal electric condition and oocytes age for activation of IVM oocytes and in vitro development of NT embryos. In vitro development of NT embryos with preactivation or non-preactivation in enucleation oocytes, cell number of IVN-IVF embryos, and NT embryos wre also examined. The results obtained were as follows; 1. The most suitable enucleation time was at 24 hpm (83.3%) rather than that of 28 hpm(69.6%) and 32 hpm(50.0%). 2. There was no difference among the fusion rates of NT embryos at the voltages of 0.75, 1.0 and 1.5 kV/cm, but the in vitro development rates to morule and blastocyst were significantly (P<0.05) higher at the voltage of 0.75(12.5%) and 1.0kV/cm (12.6%) compared to 1.5kV/cm(0%). 3. No significant difference in activation rates were seen in NT embryos stimulated for 30, 60 and 120 $\mu$sec (71.7, 85.2 and 71.9%, respectively), but the in vitro development rates to morulae and blastocyst were significantly (P<0.05) higher in the oocytes stimulated for 30 $\mu$sec (11.6%) and 60 $\mu$sec(10.7%) than 120 $\mu$sec(0.0%). 4. The fusion rates (71.0 and 87.3%) and the in vitro development rates (9.1 and 12.7%) to morula and blastocyst were seen in the NT embryos stimulated at 28 and 32 hpm under the condition of 1.0 kV/ml, 60 $\mu$sec. However, at 24 hpm the fusion rates were 64.8% and the in vitro development to morula and blastocyst were not seen. 5. The fusion rates between the 8~12, 13~17 and 18~22-cell stage of IVM-IVF embryos were not significantly different. The in vitro development rates of the fused embryos to morula and blastocyst which were received from a blastomere of 8~12, 13~17 and 18~22-cell stages of IVM-IVF embryos were 14.9, 8.3 and 6.5%, respectively. 6. The in vitro development rate of the enucleated recipient oocytes with preactivation (24.2%) to morula and blastocyst was significantly (P<0.05) higher than that of non-preactivation (12.8%). 7. The cell numbers of NT blastocyst and IVM-IVF blastocyst cultured during 7~9 days were 63$\pm$11 and 119$\pm$23, and then their the mean cell cycle number were 5.98 and 6.89, respectively.

• Korean Journal of Animal Reproduction
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• v.17 no.2
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• pp.113-120
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• 1993

To provide the optimal culture conditions for the developm,ent of in vit개 produced embryos, we have been investigated various culture media as well as co-cultrue systems using porcine cumulus cells or mouse fetal fibroblast cells. Porcine ovaries were brought to the laboratory from local slaughter house within 1 hour after slaughtering and cumulus oocytes complexes were recovered from antral follicles(3~5mm) with 23 gauge needle. To maturate follicular oocytes, cumulus oocytes complexes were washed three times with TCM-199 containing 25mM HEPES and incubated(39$^{\circ}C$, 5% CO2 in air) in various maturation media for 42 hrs. Ejaculated and liquid storaged boar spermatozoa capacitated with different sperm capacitation methods and media were rpepared for fertilizing of matured follicular oocytes in vitro. Fertilization was performed by adding 5~10${\mu}\ell$ fo capacitated spermatozoa containing 1~5$\times$105 sperm/ml to droplets. Eighteen to twenty-eight hours after sperm insemination, fertilized eggs were washed three times with culture media and transferred to the various culture media, to the culture media with a monolayer of somatic cells. The in vitro development rates of 1-cell embryos cultured with three times with culture media and transferred to the various culture media, to the culture media with a monolayer of somatic cells. The in vitro development rates of 1-cell embryos cultured with three different media, m-KRB, BECM and TCM-HEPES were 0~1.0%, showing extremely lower rates. Especially, most of embryos were observed to arrest the development beyond 4-cell stages. The rates of embryos developed to 2-, 4-, 8-, 16-, 32-cell and morula or blastocyst stage in co-culture with porcine cumulus cells and mouse fetal fibroblast cells were 61.1~67.0%, 59.0~58.0%, 42.5~43.1%, 28.4~30.2% and 20.4~21.0%, respectively. These development rates upto morula or blastocyst stages were significantly higher than those of the embryos cultured in the basic culture medium(P<0.01). These findings suggest that co-culture of in vitro fertilized eggs with porcine cumulus cells or mouse fetal fibroblast cells enhance the development of fertilized eggs to morula or blastocyst stage in vitro.

• Reproductive and Developmental Biology
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• v.37 no.1
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• pp.51-55
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• 2013

The present study was conducted to examine the effect of antioxidant treatment during parthenogenetic activation procedure on the reactive oxygen species (ROS) levels and in vitro development of porcine parthenogenetic embryos. Porcine in vitro matured oocytes were activated by a combination of electric stimulus and 2 mM 6-dimethylaminopurine (6-DAMP) before in vitro culture. During the activation period, oocytes were treated with $50{\mu}M$ ${\beta}$-mercaptoethanol (${\beta}$-ME), $100{\mu}M$ L-ascorbic acid (Vit. C) or $100{\mu}M$ L-glutathione (GSH). To examine the ROS level, porcine parthenogenetic embryos were stained in $10{\mu}M$ dichlorohydrofluorescein diacetate ($H_2DCFDA$) dye 20 h after culture, examined under a fluorescence microscope, and the fluorescence intensity (pixels) were analyzed in each embryo. The parthenogenetic embryos were cultured for 6 days to evaluate the in vitro development. The apoptosis was measured by TUNEL assay. The $H_2O_2$ levels of parthenogenetic embryos were significantly lower in antioxidant treatment groups ($26.9{\pm}1.6{\sim}29.1{\pm}1.3$ pixels/embryo, p<0.05) compared to control ($33.2{\pm}1.7$ pixels/embryo). The development rate to the blastocyst stage was increased in antioxidant treatment groups (32.0~32.5%) compared to control (26.9%, p<0.05), although, there was no difference in apoptosis among groups. The result suggests that antioxidant treatment during parthenogenetic activation procedure can inhibit the ROS generation and enhance the in vitro development of porcine parthenogenetic embryos.

• Korean Journal of Animal Reproduction
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• v.14 no.3
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• pp.223-230
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• 1990

This experiment was carried out to investigate in vitro maturation rate of pig follicular oocytes cultured from 30 to 48hr in TCM 199 supplemented with gonadotropins(FSH, LH) and estradiol-17$\beta$ and in vitro fertilization with ejaculated sperm preincubated in BO medium containing 2mM caffein and development of IVF oocytes. The results obtained in this experiments were as follows ; 1. In addition of hormones, in vitro maturation rate of follicular oocyte increased gradually from 36hr and 74.47% at 48hr in addition of hormones, but there was no differences among in vitro maturation rates after 36hr of culture. 2. Penetration rate of pig oocytes matured in FSH＋LH＋E2 and FSH＋E2 was 71.8%, 71.0% and significantly increased by the addition of hormones. 3. Percentage of developed oocytes was 44.4% for oocytes matured in FSH＋LH＋E2-added medium and 48.7% for oocytes matured in FSH＋E2-added medium, respectively. 4. Two to 16 cells stage embryos were obtained only when pig oocytes matuerd in vitro in hormones-added medium and 72hr after IVF. 5. From present results, it is concluded that gonadotropins and estradiol17$\beta$ can enhance in vitro fertilization and subsequent development as well as in vitro maturation pig follicular oocytes.

• Korean Journal of Animal Reproduction
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• v.20 no.3
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• pp.315-322
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• 1996

The study was conducted to determine the optimal glucose, superoxide dimutase(SOD) and catalase levels during the in vitro culture of porcine oocytes matured and fertilized in vitro for morulae and blastocyst development. Oocytes were cultured for 0~8 days in TCM-199 medium supplemented with 20% FCS, different glucose, SOD and catalase levels. The results are summairzed as follows ; 1. The in vitro developmental rates of porcine oocytes cultured in TCM-199 medium containing 0.1, 0.3, 0.5, 1.0, 3.0 mM glucose levels 0~3 and 0~8 days after insemination were 22.8, 24.2, 21.9, 20.0, 12.1 and 21.9, 26.7, 25.0, 22.6, 16.7%, respectively. 2. The in vitro developmental rates of porcine oocytes cultured in TCM-199 medium containing 100, 200, 300, 500 $\mu\textrm{g}$/ml SOD levels 0~3 and 0~8 days after insemination were 16.7~23.3 and 16.7~25.0%, respectively. High levels of SOD(500 $\mu\textrm{g}$/ml) significantly reduced the rates of molurae and blastocysts stage(P<0.05). 3. The in vitro developmental rates porcine oocytes cultured in TCM-199 medium containing 100, 200, 300, 500 $\mu\textrm{g}$/ml catalase levels 0~3 and 0~8 days after insemination were 18.8~26.7 and 19.4~28.1%, respectively, and there was significant differences on the development to the molurae and blastocysts stage among the cumulus cells and glucose levels.

• Proceedings of the KSAR Conference
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• 2000.10a
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• pp.9-9
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• 2000

The mammalian ovary has a large number of primordial and preantral follicles, which are a potential source of oocytes for the in vitro mass production of embryos. Several in vitro culture systems have been developed to support the growth and development of oocytes from mouse preantral follicles. Under the appropriate condition, meiotically incompetent oocytes from preantral follicles can grow to final size and complete nuclear maturation in vitro. Furthermore, the successful production of live young from in vitro grown and matured oocytes demonstrates that oocytes from preantral follicles are able to acquire full developmental capacity in vitro. However, the efficiency of in vitro production of embryos from mouse preantral follicles is still low. In farm animals as well as human, the growth of oocyte from preantral follicle to the meiotic competence stage has yet to be demonstrate. Therefore, further studies to improve the culture condition or to develope new culture system should be needed in the future. In addition, the visible progress in the establishment of the in vitro culture system for preantral follicles of farm animals and human could help to enlarge the populations of valuable agricultural, phamaceutical product-producing, and endangered animals, and to rescue the oocytes of women about to undergo clinical procedures that jeopardize oocytes.

• Korean Journal of Animal Reproduction
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• v.21 no.4
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• pp.389-396
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• 1997

Arrest in embryo development during in vitro culture has been reported in various mammals. Although some cause of the arrest have been suggested, little is known of the way that can overcome the arrest using in vitro culture system. The antioxidant, $\beta$-mercaptoethanol($\beta$-ME), has been shown to play an important role in embryo development. This study was designed to examine the effect of $\beta$-ME on the developing boving embryos produced in vitro by IVM and IVF. To select a, pp.opriate concentration of $\beta$-ME during whole culture period (7 days), various concentrations (10, 50 and 100$\mu$M) of $\beta$-ME were added to the CZB medium and their effects was significantly higher in 100$\mu$M of $\beta$-ME. The effects on development of embryos cultured with and without somatic cells to blastocyst stage were greater in FCS treatment (56.6 and 29.3%) than in BSA treatment(25.5 and 12.8%). We also evaluated the effects of $\beta$-ME addition on the blastocyst formation when embryos at different stages were exposed to 100$\mu$M $\beta$-ME. $\beta$-ME promoted increased development of embryo to blastocyst stage and the effect was greater in 6-cell to morula embryos than in embryos fewer than 4-cells at the initiation of treatment. The results suggested that $\beta$-ME can improve bovine embryo development by overcoming the arrest in early development.

• Journal of Embryo Transfer
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• v.24 no.3
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• pp.145-150
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• 2009

This study was conducted to examine the effects of human follicular fluid and gonadotropin (FSH+HCG+rhEGF) on in vitro maturation, fertilization and development of human immature oocytes. Cumulus-oocyte complexes (COCs) were collected following for in vitro fertilization and embryo transfer (IVF-ET) cycles of the patients. At the time of oocytes collection, oocytes were classified into MII, MI and GV in accordance with their appearance (MII: Fully mature oocyte at metaphase II of meiosis; MI: Nearly mature oocytes at metaphase I of meiosis; GV: Immature oocytes at prophase I of meiosis). After controlled ovarian stimulation using gonadotropin(FSH) and human chorionic gonadotropin (HCG) in 70 ICSI cycles, 158 MI to MII matured oocytes were intracytoplasmic sperm injection (ICSI) ${\sim}4$ h after in vitro culture and 553 MII oocytes were ICSI after denudation. The aspirated MI and GV oocytes were cultured in culture medium containing 10% (v/v) serum protein substitute (SPS), 10% (v/v) human follicular fluid (hFF) and 10% (v/v) serum protein substitute (SPS)+1 IU/ml FSH+10 IU/ml HCG+10 ng/ml recombinant human epidermal growth factor (rhEGF). The maturation rate of immature oocytes was similar among the three group. When maturation medium was supplemented with 10% SPS, 10% hFF or gonadotropins, the fertilization rate of in vitro matured oocytes was higher in 10% SPS (80.0%), but there was no statistical significance (78.2%; hFF, 76.9%; gonadotropin, p>0.05). The development rate of human embryos developed to $6{\sim}8$ cells were not significant difference in the medium containing SPS, hFF and gonadotropins (65.6%, 65.9% and 66.7%). The results of these study suggest that human follicular fluid and gonadotropins supplemented in the culture medium was not effected on the in vitro maturation, fertilization and development of human immature oocytes.

• Reproductive and Developmental Biology
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• v.41 no.1
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• pp.17-23
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• 2017

The oocyte undergoes various events during in vitro maturation (IVM) and subsequence development. One of the events is production of reactive oxygen species (ROS) that is a normal process of cell metabolism. But imbalances between ROS production and antioxidant systems induce oxidative stress that negatively affect to mammalian reproductive process. In vitro environments, in vitro matured oocytes have many problems, such as excessive production of ROS and imperfect cytoplasmic maturation. Therefore, in vitro matured oocytes still have lower maturation rates and developmental competence than in vivo matured oocytes. In order to improve the IVM and in vitro culture (IVC) system, antioxidants, vitamins were added to the IVM, IVC medium. Antioxidant supplementation was effective in controlling the production of ROS and it continues to be explored as a potential strategy to overcome mammalian reproductive disorders. Based on these studies, we expect that the use of antioxidants in porcine oocytes could improved maturation and development rates.

• Journal of Embryo Transfer
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• v.10 no.2
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• pp.131-138
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• 1995

Essential and non-essential amino acids supplemented to culture medium stimulate mammalian embryo development in vitro. Amino acids such as glycine, taurine and alanine are concentrated in the lumen of oviduct and uterus and it can he thought that these amino acids may have physiological role on fertilization and embryo development. Our aim of this experiment was to investigate the effects of essential and non-essential amino acids, taurine or glycine supplemented to fertilization medium on the cleavage and subsequent in vitro development of bovine oocytes matured and fertilized in vitro. Immature oocytes were obtained from slaughtered Holstein cows and heifers and matured in TCM199 containing 10% fetal calf serum, 2.5 $\mu$g /mL of FSH and LH and 1 $\mu$g / mL of estradiol with granulosa cells in vitro. After maturation, oocytes were coincubated with sperm in fertilization medium supplemented with Minimum Essential Medium (MEM) essential and non-essential amino acids, taurine (3.75 mM) or glycine (10 mM) for 30 hours in vitro. Inseminated oocytes were cultured in synthetic oviduct fluid medium (SOEM) containing MEM essential, non-essential amino acids and 1 mM glutarnine up to 8 days after fertilization.Supplementation of fertilization medium with MEM essential and non-essential amino acids lowered significantly (p<0.05 and p<0.001) the cleavage rate after 30 hours of IVF (53.3%) and at Day 3 (62.7%: Day 0: the day of I VF) compared to control (64.3% and 77.3%, respectively). Subsequent developmental rates to morulae (Mo) and expanding blastocysts (ExBL) also significantly decreased (p<0.001 and p<0.05 for Mo and ExBL) when oocytes were coincubated with sperm in the medium containing MEM amino acids. Taurine added to fertilization medium have not increased the cleavage rate over the control, whereas glycine showed significantly lower (p<0.01) cleavage rate at Day 3 than that of taurine, but there was no significant difference in the developmental rates to Mo and ExBL of bovine embryos irrespective of the supplementation of taurine or glycine to fertilization medium. In conclusion, supplementation of fertilization medium with essential and non-essential amino acids, taurine or glycine has no beneficial effect on in vitro cleavage and development of bovine oocytes matured and fertilization in vitro.