• Korean Journal of Animal Reproduction
• /
• v.22 no.4
• /
• pp.425-435
• /
• 1998

To improve the efficiency of nuclear transplantation in bovine, in this study the development in vitro of nuclear transferred (NT) embryos was compared by different activation regimens of the enucleated oocytes. The effect of developmental stage and culture system of donor nuclei on fusion and development in vitro of NT embryos were also evaluated. Oocytes were collected from Hanwoo ovaries obtained from slaughterhouse and matured in Ham's F-10 supplemented with hormones. After 20~22 h maturation, the oocytes were vortexed to be free from cumulus cells and subsequently their nucleus and the first polar body were removed. Enucleated oocytes were divided into 3 groups for activation; the oocytes of group I were activated with ionomycin for 5 min and subsequently incubated in 6-dimetylarninopurine (DMAP) for 4 h, Those of group II were treated with DMAP for 4 h at 39 h after onset of in vitro maturation (IVM) and those of group III were kept in room temperature ($25^{\circ}C$) for 3 h at 39 h after onset of IVM. After in vitro fertilization (IVF) the embryos for muclear donor were cultured either by group culture (20 embryos /50 ${mu}ell$ drop) or individually (1 embryo /50 ${mu}ell$ drop) for 4 day and 5 day. At day 4 and 5 after IVF, blastomeres were separated in calcium-magnesium free medium, and then classified into small (day 5: $\leq$ 38 ${\mu}{\textrm}{m}$, day 4: $\leq$ 46 ${\mu}{\textrm}{m}$) and large (day 5 : $\geq$ 38 ${\mu}{\textrm}{m}$, day 4 ; $\geq$ 46 ${\mu}{\textrm}{m}$). The separated blastomeres were replaced into enucleated and activated recipient cytoplasm. The blastomere-oocyte complexes were fused by electrically. The NT embryos were cultured in TCM-199 containing 10% FCS in 39$^{\circ}C$, 5% $CO_2$ incubator for 7 day. The results obtained were summarized as follows; There were no differences in fusion and development to blastocyst between groups as group I (68%, 10%), group II (75%, 14%) and group III (73%, 9%), respectively. However, the cell number in blastocyst of NT embryos in group III were significantly fewer than in the other groups (P＜0.05). No differences in fusion and development to blastocyst were found between individual or group cultured and between small or large blastomeres of day 4 and day 5 donor embryos. From these results, it was concluded that the combination of ionomycin and DMAP, or treatment of DMAP at 39 h after onset of IVM were useful for the efficient of production of NT bovine embryos, and the individual cultured embryos could be simply used as donor nuclei for NT bovine embryo.

• Journal of Embryo Transfer
• /
• v.14 no.3
• /
• pp.163-169
• /
• 1999

This study was carried out to investigate the effect of co-culture system(bovine oviduct epithelial cells; BOEC) and defined culture system(modified TALP ; mTALP) on the development of IVM-IVF embryos, and survival of in vitro produced blastocysts after freezing and thawing. Occytes from the slaugheterhous ovaries were matured and fertilized using general protocol. The results obtained were as the following: 1. Survival rates of frozen-thawed blastocysts using 10% glycerol as cryoprotectant was higher in day 7 blastocysts than in Day 8 and 9 blastocysts from co-cultrue system, but survival rate of frozen-thawed blastocysts was higher in Day 10 blastocysts than in day 8 and 9 blastocysts from defined culture system. Regardless of their age, survival rate of frozen-thawed blastocysts was significantly higher (p<0.05) in co-culture system than in defined culture system. 2. The cell number of blastocysts was significanlty higher (p<0.05) in Day 7 blasotcysts than in Day 8 and 9 blastocysts from co-cultures, but the cell number of blsstocysts was significantly higher (p<0.05) in Day 10 blastocysts than in Day 8 and 9 blastocysts from defined culture system. Regardless of the culture system, blastocysts with higher cell number showed higher survival rates after freezing and thawing.

• Journal of Embryo Transfer
• /
• v.18 no.3
• /
• pp.237-242
• /
• 2003

These studies were carried out to establish an effective in vitro embryo transfer methods by analyzing several factors. The base media were TCM-199 solution for in vitro maturation(IVM) of bovine follicular oocytes and Fer-TALP solution for in vitro fertilization(IVF) and CRlaa medium for in vitro culture(IVC). IVC used the fertilized oocytes of 24-hr culture (day 1)after IVF. Embryos were cultured in drop-culture that contained 25 embryos per 10${mu}ell$. Blastocysts cultured for 7 to 9 in vitro were transferred to recipients. The results obtained were as follows: 1. The pregnancy rate according to different region of embryo transfer were 33.8％, 48.1％, 45.0％ and 35.3％ respectively. 2. The pregnancy rate according to the parity of recipient when embryos were transferred to nulliparous (42.9％) was higher than that of 1∼3nd parlous(36.9％), however there were not show significant difference each other. 3. According to the stage of blastocyst, the pregnancy rate when middle blastocysts (MB) (45.5％) were transferred to recipients were higher than that of late blastocysts (LB) (41.0％). 4. When IVF-derived blastocysts cultured for 7 to 9 day were transferred to recipients, the pregnancy rate was higher 7 day of blastocyst than that of 8 day or 9 day of blastocyst. The results of embryo transfer according to the regions, the parity of recipient and the development stage showed that blastocyst formed for 7day transferred to nulliparou were higher pregnancy rate than others.

• Korean Journal of Animal Reproduction
• /
• v.24 no.1
• /
• pp.89-95
• /
• 2000

This study was to establish an effective dilution technique in a vitrification of bovine blastocysts for the field trial. For vitrification, blastocysts were exposed in glycerol (G) and ethylene glycol (EG) mixture in m-DPBS supplemented with 10% FBS. Blastocysts were first exposed to 10% (v/v) G for 5 min, and subsequently were transferred to 10% G plus 20% EG (v/v) for 5 min. Finally, embryos were transferred to 25% G plus 25% EG (v/v) for 30 see and were placed in nitrogen vapor for 3 min, and then were plunged into L$N_2$. At thawing, the straw containing blastocysts was placed in air for 10 sec, and then plunged into a water bath at $25^{\circ}C$ until all ice had disappeared. They were placed in $25^{\circ}C$ and 36$^{\circ}C$ water according to treatment group for different time. Also, in vitro survival was assessed by the re-expansion and hatched rates at 24 hand 48 h postwarming, respectively. The results obtained in these experiments were summarized as follows; 1) In the survival rates of vitrified bovine blastocysts according to different dilution time at thawing, the data of 1 min group (86.6, 56.6%) were higher than those of other treatment groups (2 min; 93.5, 35.4%, 2.5 min; 76.9, 30.7%, 3 min; 88.8, 36.1% and 3.5 min; 83.7, 8.1%). 2) When the in vitro survival of vitrified groups according to different developmental stage was examined at 48 h after thawing using 1 min dilution method, the hatching rates of fast developed embryos (expanded blastocyst: 81.3%: early hatching blastocyst: 86.2%) were higher than that of delayed developed one (early blastocyst: 46.6%). 3) In addition, when the in vitro survival of vitrified groups according to different embryo age was compared, the hatched rates at 48 h after thawing of Day 7 (66.6%) and Day 8 embryos (60.0%) were significantly higher than that of Day 9 embryos (22.7%) (P＜0.05). These results demonstrate that vitrified bovine IVM/IVF/IVC blastocysts can be successfully survived in vitro using one-step dilution (1 min) method.

• Journal of Embryo Transfer
• /
• v.19 no.1
• /
• pp.1-10
• /
• 2004

These studies were carried out to improve the reproductive efficiency through embryos transfer of Hanwoo IVM/IVF embryos. Following routine IVM/IVF procedure, oocytes and zygotes were cultured far 40 to 44 h in CRlaa medium with BSA. Then 2 to 8-cell embryos were removed the cumulus cell and were cultured in CRlaa medium containing 10% fatal bovine serum and 2.5 mM taurine in 5% $O_2$ and 5% $CO_2$ at 38.5$^{\circ}C$. The fresh embryos of the morulae and blastocysts cultured for 6 to 9 days in vitro or the frozen-thawed embryos were transferred into recipients. The pregnancy rates of the blastocyst produced for 6, 7, 8, and 9 days in vitro culture were 59.4, 68.2, 66.0 and 100%, respectively. In the developmental stage, pregnacy rates of early blastocysts (61.1%), blastocysts(64.7%) and expanded blastocysts(69.5%) were higher than that of morulae stage(20.0%). The pregnancy rates according to the corpus luteum grades of A, B and C in recipients were 73.6, 62.9 and 50.0%, respectively. Effects of donor-recipients synchrony of after day 2, 1 and 0, before day 1 and 2 on the pregnancy rates were 35.7, 65.5, 72.6, 67.9 and 60.0%, respectively. Pregnancy rates of the body condition score of recipients $\leq$2(71.3%) were higher than those of $\geq$3.0 score(40.0%). The pregnancy rates according to the parity of recipients when embryo was transferred to cow(70.6%) was higher than in heifer(59.1%). The pregnancy rates according to hormone treatment before embryo transfer were 69.9% in hCG + GnRH administration group and 63.0% in control group. Fresh and frozen-thawed embryos on the pregnancy rates were 70.6 and 36.4%, respectively. Pregnancy rates in single and AI+single was 90.0% and 64.8%. Pregnancy rates in twin induction was better than in single. These results indicate that pregnancy rates after transfer were affected on the embryo ages, donor-recipient synchrony, body condition score of recipients, corpus luteum status, parity and hormone treatment to recipients.

• Clinical and Experimental Reproductive Medicine
• /
• v.26 no.2
• /
• pp.231-238
• /
• 1999

The objective of this study was to examine the effect of developmental stage and embryo age of in vitro produced bovine blastocysts after vitrification and thawing. In vitro cultured day 8 blastocysts after IVF were equilibrated 20% ethylene glycol (EG) for 3 min. and were vitrified using EFS40, which is consisted of 40% EG, 18% ficoll, 0.3M sucrose and 10% FBS added in mDPBS for 30 sec. before being plunged into $LN_2$. Also, survival in vitro was assessed by re-expansion and hatching or hatched at 24 hand 48 h postwarming, respectively. The results obtained in these experiments were summarized as follows; 1) When the embryos were cultured for 8 day after IVF, 41.0% of the cleaved embryos developed to the blastocysts (early; 7.6%, expanded; 22.9%, hatching; 4.6% and hatched; 5.9%). 2) When the embryos were exposed or vitrified to the freezing solution, the re-expansion of vitrified embryos (73.3%) was significantly lower than that of control and exposed embryos (100, 97.0%) (p<0.05). But the formation rate of hatching or hatched blastocysts of vitrified embryos (66.7, 46.7%) at 48h after thawing was similar to that of exposed embryos (66.7, 39.4%) but not control (100, 100%) (p<0.01). However, in the total cell numbers of those developed hatched blastocysts, there were not significantly different among the treatment groups. 3) When the embryo survival rates by different developmental stage were examined, the re-expansion was not different among the groups $(64.5{\sim}75.6%)$. After warming 48 h, the hatching and hatched formation of early blastocysts (25.8, 9.7%) was significantly lower than those of expanded (69.7, 39.4%) and hatching blastocysts (53.3, 43.3%) (p<0.05). 4) In addition, when the expanded blastocysts at day 7, 8 and 9 were vitrified, the re-expansion of day 8 and 9 embryos was significantly lower than that of day 7 (day 7; 93.9%, day 8; 75.8% and day 9; 87.5%) (p<0.05). However, the rates of development to hatched blastocysts were no difference among the groups (day 7; 36.4%, day 8; 36.4% and day 9; 31.3%). These results suggested that in vitro produced expanded or hatching blastocysts can be efficiently cryopreserved by the two-step vitrification method using EFS40.

• Korean Journal of Animal Reproduction
• /
• v.24 no.1
• /
• pp.69-76
• /
• 2000

This study was carried out to improve of effective culture system on development of IVM/IVF/IVC bovine embryos. The cumulus-oocyte-complexes (COCs) collected from Korean cattle ovaries harvested at a local abattoir were matured in 50 ${mu}ell$ of TCM199 supplemented with 10% fetal bovine serum (FBS) and hormones (35 $\mu\textrm{g}$/$m\ell$ FSH, 10 $\mu\textrm{g}$/$m\ell$ LH, 1$\mu\textrm{g}$/$m\ell$ estradiol 17 $\beta$ under paraffin oil at 39$^{\circ}C$ in a humidified atmosphere of 5% $CO_2$in air. At 24 hrs after culture, matured oocytes were fertilized in vitro for 22~24 hrs with motile semen in which obtained by centrifugation of a frozen thawed semen on Percoll-density gradients (45% vs. 90%) at 500 g for 20 min. The presumptive zygotes were divided into three experimental groups. Single egg (Group 1), 25 (Group 2) or 50 eggs (Group 3) were cultured on cumulus cell in 50 ${mu}ell$ TCM199 supplement with 10% FBS for 6~9 days after fertilization. In vitro developmental rates into the blastocysts in the groups 2 and 3 were significantly (P＜0.05) higher than those of group 1 (37,27 vs. 6%, respectively). Cell number of blastocysts obtained in groups 2 and 3 at day 8 were significantly (P${mu}ell$) resulted in higher developmental competence and cell number of bovine blastocysts produced in vitro than those the culture of single embryos with cumulus cells.

• Clinical and Experimental Reproductive Medicine
• /
• v.22 no.2
• /
• pp.105-108
• /
• 1995

본 연구는 혈청 무첨가 단순배양액인 CR1이 체외에서 생산된 소 수정란의 체외 배발생에 미치는 영향을 검토하고자 실시하였다. 본 연구에서 얻어진 결과를 요약해보면, 1) 총 1250개의 체외성숙 난자로 부터 체외 수정결과 본 실험의 목적상 이용될 수 있는 1,025개 (82.0%)의 분할란 (>1세포기)을 얻을 수 있었으며, 체외배양 결과 배반포기와 부화율은 각각 27.1%와 20.2%였다. 2) CR1 배양액은 소난포란 (>1세포기)의 체외발생시 난관상피세포, 난구세포, 영양배엽세포 등의 체세포와 공동배양을 유도하지 않고서도 높은 배발생율을 얻을 수 있었으며, 이러한 결과로 미루어 볼때 CR1은 난자의 체외배양시 난자성장촉진 인자를 연구하는데 효과적으로 사용될 수 있다는 것을 시사한다.

• Journal of Embryo Transfer
• /
• v.17 no.3
• /
• pp.211-218
• /
• 2002

These studies were carried out to investigate the effects of the addition of amino acids and FBS as source of exogenous nitrogen fixation added to medium on in vitro production of blastocyst derived from bovine follicular oocytes. The base medium was TCM-199 solution for in vitro maturation(IVM) of bovine follicular oocytes and Fer-TALP solution for in vitro fertilization(IVF) and YS solution for in vitro culture(IVC). IVC used the fertilized oocytes of 24-hr culture (day 1) after IVF. Rmbryos were cultured in drop-culture that contained 25 embryos per 10 ${mu}ell$. The results obtained are as follows: 1 The developmental rates of fertilized oocytes to blastocyst that developed from YS solution with NEAA derived from MEM alone were higher than those of YS solution without NEAA. 2. The developmental rates of fertilized oocytes to blastocyst that developed from YS solution with EAA derived RPMI 1640 alone were significantly higher than those of YS solution without EAA (p<0.05). 3. When added to EAA on day 5 after NEAA supplementation on day 1, the developmental rates of hatched blastocyst and blastocyst to hatched blastocyst were improved. 4. When removed to EAA on day 3, day 4 and day 5 from medium after NEAA and EAA supplementation on day 1. the developmental rates of blastocyst to hatched blastocyst were reduced. 5. When added to FBS as source of exogenous nitrogen fixation, the developmental rates of blastocyst and hatched blastocyst that developed from the later culture higher(day 5) than those of the early culture.

• Korean Journal of Animal Reproduction
• /
• v.25 no.1
• /
• pp.19-28
• /
• 2001

The present study was undertaken to investigate the effects of cooling rate and equilibration time on the survival, in vitro maturation and development to embryos of frozen-thawed bovine immature oocytes(Germinal Vesicle Stage). The cryoprotectants are used 10% ethylene glycol(EG) as permeating cryoprotectant and 0.05M soc.ose(S) or trehalose(T) as low molecular weight nonpermeating cryoprotectants and 5% ficoll(F) or polyvinylpyrrolidone(PVP) as high molecular weight nonpermeating cryoprotectants. Four freezing solution were uysed in this experiment(EFT: 10% EG + 5% F + 0.05M T, EFS: 10% EG + 5% F + 0.05M S, EPT: 10% EG + 5% P + 0.05M T, EPS: 10% EG + 5% P + 0.05M S). The best equilibration time and freezing solution was 15 min in EPT(83% survival rate of frozen-thawed bovine immature oocytes). When frozen-thawed bovine oocytes were cultured following IVM and IVF, there was no significant difference in cleavage and development rates among the EFT, EFS, EPT and EPS solutions. When 9 blastocysts derived from frozen bovine oocytes were transferred to 6 recipients, two recipients were pregnant. And one was aborted at 45 days of pregnancy and the other had a stillbirth.