Eu Gine Lee

Seoul National University, Sŏul, Seoul, South Korea

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Publications (5)7.89 Total impact

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    ABSTRACT: The susceptibility of embryos to reactive oxygen species (ROS) varies in different stages of embryo development. The present study evaluated temporal effects of alpha-tocopherol and L-ascorbic acid on the porcine embryo development, and investigated whether a single or twice supplements of these two antioxidants at a divided concentrations favors the embryo development. In order to determine temporal effects of alpha-tocopherol and/or L-ascorbic acid, 100 microM alpha-tocopherol or 200 microM L-ascorbic acid were supplemented to the North Carolina State University (NCSU)-23 embryo culture media at 0, 48, 96 and 120 h of culture. In another set of experiments, the concentration was divided into two equal halves, i.e., 50 microM alpha-tocopherol and 100 microM L-ascorbic acid, and supplemented twice at 0 and 48, 0 and 96, or 48 and 96 h of culture. Supplementing culture media with 100 microM alpha-tocopherol for the entire culture period of 168 h or starting from the 48 h of culture yielded higher blastocyst percentage compared with the control or starting from the 96 or 120 h of culture. L-Ascorbic acid (200 microM) alone or together with alpha-tocopherol (100 microM) with a single supplement did not affect the frequency of blastocyst formation or number of cells in blastocyst. L-ascorbic acid with a divided supplements yielded higher blastocyst percentage compared with the control. No synergistic effect was observed on embryo development at a single supplement of these antioxidants. Although, at divided supplements higher blastocyst percentage was observed compared with control group, no further beneficial effect was observed compared with alpha-tocopherol or L-ascorbic acid alone. Our results demonstrated that the embryotrophic effects of alpha-tocopherol and/or L-ascorbic acid, in terms of frequency of blastocyst formation and number of cells in blastocyst, depends on the concentration and supplementation timing.
    No preview · Article · Aug 2007 · Animal Reproduction Science
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    ABSTRACT: 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 CaCl2 and 0.1 mM of MgCl2 for 30 μs 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 H2O2 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 μM 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 μM L-ascorbic acid (50.0 and 56.4, respectively) compared to 0 and 200 μM L-ascorbic acid (36.5 and 39.8, respectively). L-ascorbic acid reduces the H2O2 level in developing embryos in a dose-dependant manner. The H2O2 level (pixels/embryos) was 191.5, 141.0, 124.0 and 163.3 for 0, 50, 100 and 200 μM L-ascorbic acid, respectively. So, we recommend to supplement 50 or 100 μM L-ascorbic acid in porcine in vitro culture medium.
    No preview · Article · Mar 2007 · Asian Australasian Journal of Animal Sciences
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    ABSTRACT: Insulin-like growth factor (IGF)-I is a receptor-mediated autocrine and/or paracrine growth and/or survival factor for mammalian embryo development. It is known to promote the growth and development of mouse preimplantation embryos. The present study was designed to investigate the effects of IGF-I (50 ng/ml), anti-IGF-I receptor antibody (50 ng/ml) and their combination on porcine preimplantation embryo development. Furthermore, the mechanism underlying the embryotropic effects of IGF-I was evaluated by monitoring the incidence of apoptosis and expression of apoptosis-related genes. In both in vitro fertilized (IVF) and somatic cell nuclear transfer (SCNT) embryos, culturing with IGF-I increased the rate of blastocyst formation and this embryotrophic effect was neutralized by culturing with IGF-I along with anti-IGF-I receptor (IGF-IR) antibody. Culturing IVF and SCNT embryos with IGF-I significantly increased the number of total cells in blastocysts and decreased the number of apoptotic nuclei. These effects of IGF-I were also neutralized by culturing with IGF-I along with anti-IGF-IR antibody. Expression of the anti-apoptotic Bcl-2 gene was increased, while expression of the pro-apoptotic Bax was decreased in both IVF and SCNT embryos cultured with IGF-I. In both IVF and SCNT embryos, anti-IGF-IR antibody along with IGF-I neutralized the effect of IGF-I on expression of Bcl-2 and Bax genes. In conclusion, the present study demonstrated that IGF-I through its specific receptors improved the developmental competence of IVF and SCNT embryos by decreasing the incidence of apoptosis and regulating apoptosis-related genes in porcine preimplantation embryos.
    No preview · Article · Dec 2006 · Molecular Reproduction and Development
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    ABSTRACT: The present study was conducted to examine the comparative efficacy of potassium simplex optimization medium (KSOM) and North Carolina State University (NCSU)-23 medium supplemented with beta-mercaptoethanol (beta-ME) and amino acids (AA) on the developmental competence of porcine in vitro fertilized (IVF) embryos. Four experiments were conducted. KSOM and NCSU-23 medium were used to culture porcine parthenogenetic (Exp. 1) and IVF (Exp. 2) embryos. KSOM and NCSU-23 were equally effective in supporting porcine parthenogenetic and IVF embryo development from the 1-cell stage to blastocysts. The NCSU-23 medium (Exp. 3) and KSOM (Exp. 4) were supplemented with amino acid (AA; 5 microl/ml non-essential amino acids + 10 microl/ml essential amino acids) and/or 10 microM beta-mercaptoethanol (beta-ME). The quality of blastocysts from Exp. 3 and 4 was evaluated by counting the number of total cells and determining the ratio of the inner cell mass (ICM) to trophoectoderm (TE) cells. Supplementing with AA and beta-ME or beta-ME alone in NCSU-23 produced significant (p<0.05) differences in terms of rate of cleavage to the 2- to 4- cell (80.8 to 85.4% vs. 73.6%) and blastocyst (30.4 to 30.5 vs. 23.5%) stages and the number of TE (51.4 to 53.8 vs. 35.8) and total cells (67.2 to 71.2 to 48.8) over the control group. On the other hand, supplementing KSOM with AA and/or beta-ME produced significant (p<0.05) differences in terms of rate of cleavage to the 2- to 4-cell (78.8% vs. 67.7%) and morula (57.8% vs. 46.3%) stages and the number of ICM (18.6 to 19.2 vs. 11.6) and total cells (62.8 to 70.6 vs. 42.8) over control group. In conclusion, our study demonstrates that both KSOM and NCSU-23 medium supplemented with AA and beta-ME and/or only beta-ME alone are superior to normal KSOM and NCSU-23 for porcine IVF embryo culture in terms of embryo developmental competence and quality.
    No preview · Article · Nov 2006 · Journal of Reproduction and Development
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    ABSTRACT: This study investigated the embryotrophic effects of ethylenediaminetetraacetic acid (EDTA) and hemoglobin (Hb) on porcine preimplantation embryo development. Porcine embryos produced by in vitro maturation/fertilization were cultured for 6 days in modified North Carolina State University-23 medium (mNCSU-23) supplemented with EDTA and/or Hb. In Exp. 1, culturing porcine zygotes with 100 microM EDTA significantly increased cleavage frequencies (85.3%) at 48 h post insemination and the number of inner cell mass (ICM) (9.6+/-5.5) compared to the control (7.0+/-2.8). However, 100 microM EDTA did not improve blastocyst formation compared to 0, 1 or 10 microM EDTA. In Exp. 2, in vitro fertilized oocytes were cultured with 0, 1 or 10 microg/ml Hb. Culturing with Hb did not promote porcine embryo development, but significantly increased the cell numbers of blastocysts in 1 microg/ml Hb compared to 0 or 10 microg/ml Hb. In Exp. 3, culturing embryos with 100 microM EDTA+1 microg/ml Hb significantly improved frequencies of cleavage, blastocyst formation, and total cell numbers in blastocysts compared to the control. Moreover, 100 microM EDTA, 1 microg/ml Hb and their combination reduced reactive oxygen species (ROS) accumulation and decreased the incidence of apoptosis. In conclusion, the present study clearly demonstrated that the combining treatment of EDTA and Hb improved IVF porcine embryo development.
    No preview · Article · Aug 2006 · Theriogenology