This study was to analyse the usability of morphological evaluation of vitrified-thawed oocyte before somatic cell nuclear transfer (SCNT) using Oosight imaging system to show spindle. For the vitrification, in vitro matured bovine MII oocytes were treated by two-step freezing medium without (control group) or with 5 ug/ml cytochalasin-b (CCB group). In Exp. 1, after thawing, recovered oocytes in each treatment group were assessed by live image using Oosight imaging system or/and cytoskeletal protein image using immunostaining. In Exp. 2, in each treatment group the in vitro developmental potential of frozen-thawed bovine oocytes post evaluation using Oosight imaging system and then SCNT was investigated. The SCNT embryos were cultured in CR1aa medium supplemented with 10% FBS, 1 mM EGF and 1 mM IGF at 38.5 C in 5% O2 and 5% CO2 in air for 8 days. In Exp.1, the rates of in vitro survival, morphological good grade and spindle normality of CCB treatment group (91.1%, 54.2% and 55.5%) were better than those of control group (86.1%, 48.5% and 48.5%). After SCNT using vitrified-thawed oocyte, the rates of fusion, reconstructed embryos and blastocyst development were also high in CCB treatment group (66.6%, 36.4% and 3.0%) than control group (60.0%, 27.3% and 0%). These results demonstrated that the identification of morphological spindle image of the vitrified-thawed bovine oocytes using Oosight imaging system helps to predict the SCNT embryo quality.

The production of transgenic animals using somatic cell nuclear transfer (SCNT) has been widely described. A critical problem in the production of transgenic animals is the uncontrolled constitutive expression of the foreign gene which occasionally results in serious physiological disorders in the transgenic animal. In this study, we designed three different expression vectors that express the hEPO gene. hEPO is a hormone produced by the kidney that promotes the formation of red blood cells by the bone marrow. For the in vitro production of transgenic embryos, the different expression vectors were transduced into holstein ear fibroblast cells, respectively, and GFP expressed donor cells were transferred into enucleated oocytes, and then the reconstructed SCNT embryos were developed into pre-implantation stage. From three replicates, GFP expressed 112 transgenic SCNT embryos were produced. When their cleavage rate and blastocyst rate were compared with non-transgenic SCNT embryos, the results were presented into 73.2% vs. 76.9% and 26.8% vs. 30.6%, respectively, there were no differences. Also, total cell number and ICM cell numbers of day 8 blastocysts were statistically not different between the transgenic SCNT groups (120.6±7.9 and 31.4±8.2) and control SCNT group (128.3±4.8 and 35.3±4.0). The GFP expression levels were presented consecutively high during the culture of transgenic SCNT embryos. By analysis of semi-quantitative RT-PCR, the relative expression levels of hEPO mRNA and pluripotent gene were determined. These results demonstrated that the hEPO expressed transgenic bovine embryos can be efficiently produced in vitro by SCNT technique, while their potential of cloned animal production have to be examined in further study.

Somatic cell nuclear transfer (SCNT) is an efficient technique which has been successfully applied to developmental biology, and resulted in the production of offspring from various species. It offers many opportunities in basic and medical research as well as endangered species preservation. On the other hand, embryonic stem (ES) cells are useful research tools for genetic engineering and developing disease models. In previous study, we established bovine IVF embryo derived ES cell line which can be grow indefinitely as undifferentiated cell state. In this study, we compared the effect of two different age cells (bovine ES cell; JNU-ibES-05 or adult ear fibroblast cell) on in vitro developmental potential of bovine SCNT embryo. To produce SCNT embryos, the ES cells or somatic cells were dissociated and transferred into enucleated MⅡ oocytes, and cleaved reconstructed embryos were cultured in CR1aa medium containing 10% FBS, 1 ug/ml epidermal growth factor (EGF) and 1 ug/ml insulin growth factor (IGF) for 8 days. In the result, blastocyst development rate was similar between ES cell treatment group and somatic cell treatment group, 27.7% (10/36) and 28.9% (11/ 38), respectively. However, there was particular difference in development speed from day 5 post SCNT, blastocyst expanding was 1 day faster in ES cell group than in somatic cell group. This difference was analyzed by semi-quantitative RT-PCR using pluripotency, growth and cell cycle gene markers. These results demonstrated that SCNT embryo using ES cell as a donor cell has better growth potential than somatic cell, and it will be a useful tool for a transgenic animal production.

It is known that oocytes can be activated without male contribution in vitro and develop to blastocysts which are used to isolate parthenogenetic embryonic stem (ES) cells. Differentiation capacity of the parthenogentic ES cells was rather lower than that of fertilized embryos derived ES cells, which might be the result of the absence of male genome. However, parthenogenetic ES cells might be useful research tool for genetic engineering and generating SCNT embryo derived ES cells. In our previous study, we reported that establishment of several bovine ES cell lines from in vitro fertilized (IVF) embryos named JNU-ibES. Based on this data, the objective of this study is to generate parthenogenetic ES cells and to examine their stem cell characteristics. Total 107 parthenogenetic embryos produced at day 8 or 9 were classified into their developmental stages (full expanded x 40, hatched x 67). For producing ES cells, ICM and trophetoderm-rich clumps were mechanically dissociated and were cultured on mitomycin- C treated mouse embryonic fibroblast feeder cell drop and covered with mineral oil in DMEM medium containing 20% FBS, 5 ng/ml basic FGF, 1% nonessential amino acids, and 0.55 mM b-mercaptoethanol. We obtained 20 primary parthenogenetic bovine ES (pbES)-like cell colonies. And pbES colony formation was higher in hatched blastocyst (25.4%, 16/67) than expanded blastocysts (10%, 4/40). Among those colonies, 5 pbES cell lines were successfully established and they were named as a series of JNU-pbES. These pbES cells were positively expresssed pluripotency markers such as Oct4, Nanog, TRA-1-81, SSEA-1 and alkaline phosphatase. This result demonstrated that the establishment efficiency and characteristics of pbES cell line was very similar to those of ibES cell line.

One-step dilution and direct transfer would be a practical technique for the field application of frozen embryo. This study was to examine whether Jeju Black Cattle (JBC, Korean Cattle) can be successfully cloned from vitrified and one-tep diluted somatic cell nuclear transfer (SCNT) blastocyst after direct transfer. For vitrification, JBC-SCNT blastocysts were serially exposed in glycerol (G) and ethylene glycol (EG) mixtures〔10% (v/v) G for 5 min., 10% G plus 20% EG (v/v) for 5 min., and 25% G plus 25% EG (v/v) for 30 sec.〕which is diluted in 10% FBS added D-PBS. And then SCNT blastocysts were loaded in 0.25 ml mini straw, placed in cold nitrogen vapor for 3 min. and then plunged into LN2. One-step dilution in straw was done in 25℃ water for 1 min, by placing vertically in the state of plugged- end up and down for 0.5 min, respectively. When in vitro developmental capacity of vitrified SCNT blastocyst was examined at 48 h after one-step dilution, hatched rate (56.4%) was slightly lower than that of control group (62.5%). In field trial, when the vitrified-thawed SCNT blastocysts were transferred into uterus of synchronized 5 recipients, a cloned female JBC was delivered by natural birth on day 299 and healthy at present. In addition, when the short tandem repeat marker analysis of the cloned JBC was evaluated, microsatellite loci of 11 numbers was perfectly matched genotype with donor cell (BK94-14). This study suggested that our developed vitrification and one-step dilution technique can be applied effectively on field trial for cloned animal production, which is even no longer in existence.

This study was to investigate the effect of flavonoid treatment on in vitro development of bovine somatic cell nuclear transfer (SCNT) embryos, and their pregnancy and delivery rate after embryo transfer into recipient. In experiment 1, to optimize the flavonoid concentration, parthenogenetic day 2 (≥ 2-cell) embryos were cultured in 0 (control), 1, 10 and 20 μM flavonoid for 6 days. In the results, in vitro development rate was the highest in 10 μM flavonoid group (57.1%) among treatment groups (control, 49.5%; 1 μM, 54.2%; 20 μM, 37.5%), and numbers of total and ICM cells were significantly (p<0.05) higher in 10 μM flavonoid group than other groups. We found that 10 μM flavonoid treatment can significantly (p<0.05) decrease the apoptotic index and derive high expression of anti-oxidant, anti-apoptotic, cell growth and development marker genes such as Mn-SOD, Survivin, Bax inhibitor, Glut-5, In-tau, compared to control group. In experiment 2, to produce the cloned Jeju Black Cattle, beef quality index grade 1 bull somatic cells were transferred into enucleated bovine MII oocytes and reconstructed embryos were cultured in 10 μM flavonoid added medium. When the in vitro produced day 7 or 8 SCNT blastocysts were transferred into a number of recipients, 10 μM flavonoid treatment group presented higher pregnancy rate (10.2%, 6/59) than control group (5.9%, 2/34). Total three cloned Jeju Black calves were born. Also, two cloned calves in 10 μM flavonoid group were born and both were all healthy at present, while the one cloned calf born in control group was dead one month after birth. In addition, when the result of short tandem repeat marker analysis of each cloned calf was investigated, microsatellite loci of 11 numbers matched genotype between donor cell and cloned calf tissue. These results demonstrated that the flavonoid addition in culture medium may have beneficial effects on in vitro and in vivo developmental capacity of SCNT embryos and pregnancy rate.