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

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

• Journal of Embryo Transfer
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• v.20 no.1
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• pp.55-62
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• 2005

This study was undertaken to access the effect of collection methods on the collection efficiency, blastocyst rate and pregnancy rate after IVP embryo transfer. The ovaries of Hanwoo were obtained from an abattoir and kept on 25 to $28^{\circ}C$ and transported to laboratory within 4 hrs. The oocytes were collected by aspiration of follicles $(2\~6\;mm)$ with or without slicing of ovaries after aspiration. The oocytes were matured in vitro (IVM) for 20 to 24 hrs in TCM-199 supplemented with $10\%$ fetal bovine serum at $39^{\circ}C$ under $5\%\;CO_{2}$ in air. Following routine IVM/IVF procedure, the oocytes and presumed zygotes were cultured for three day in CRlaa medium with BSA. The cumulus cells at 2 to 8-cell stage of embryos removed then the embryos and were cultured in CRlaa medium containing $10\%$ fetal bovine serum in $5\%\;CO_{2}$ at $39^{\circ}C$. The fresh blastocysts cultured for 7 to 9 days were transferred into recipients. The numbers of oocytes recovered form two different methods, the aspiration and slicing after aspiration, were compared to know what. The number of oocytes per ovary was 8.2 and 6.5 in aspiration combining slicing, and aspiration groups, respectively (p<0.05). The cleavage rate in aspiration method are significantly (p<0.05) high than those in slicing post aspiration $(27.9\%)$, and aspiration $(25.5\%)$. The pregnancy .ate in aspiration method $(62.5\%)$ was high than that in slicing method after aspiration $(54.4\%)$. The pregnancy rates of aspiration method and slicing method after aspiration in nullipara $(58.1\%\;vs\;68.2\%)$ was high than that in pluripara $(49.5\%\;vs\;53.2\%)$. The results obtained that the increased number of oocytes per ovary in slicing method after aspiration could be better than that in aspiration method. Pregnancy rate in aspiration method was slightly higher in than that in slicing method after aspiration.

• Korean Journal of Animal Reproduction
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• v.23 no.2
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• pp.141-148
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• 1999

This study was to test whether the viability of bovine hatched blastocysts (HBs) can be maintained after vitrification and thawing. The HBs were produced in vitro at Day 9 and Day 10 after IVF, and they were classified to small (S-HBs; ø$\leq$300 ${\mu}{\textrm}{m}$) and large(L-HBs; ø＞300 ${\mu}{\textrm}{m}$) on the basis of embryo diameter using eyepiece micrometer. As freezing solution, we used EFS35 which consisted of 35% ethylene glycol (EG), 18% ficoll, 0.3 M sucrose and 10% FBS added in mDPBS. Vitrification was taken by two-step method, the HBs were equilibrated in 10% EG for 5 minutes and then shortly exposed in EFS35 and plunged into L$N_2$for 30~45 sec. After thawing, the survival rates were assessed by the re-expansion of the blastocoel during 2 h and 16 h of culture. The results obtained in these experiments were summarized as follows; 1) When the blastocysts(40.8%) recovered at Day 8 after IVF were further cultured for 24 h(Day 9 after IVF) and 48 h(Day 10 after IVF), the rates of HBs were 20.5% and 6.7%, respectively. Also, the total cell number of HBs on Day 9 was significantly higher than that of HBs on Day 10 (p＜0.01). 2) When the effects of freezing solution to the survival of Day 9 L-HBs were examined, the rate of vitrified group (75.7%) was significantly lower than 100% of control and exposed group(p＜0.05). 3) When the survival rates of vitrified HBs according to size and developmental age were examined, the data of L-HBs (75.5%) and S-HBs(63.6%) on Day 9 were slightly higher than those of L-HBs(64.3%) and S-HBs(60.7%) on Day 10. 4) Also, when the in vitro survival of Day 9 HBs was evaluated under different culture condition after thawing, the result in culture medium only (79.3%) was significantly higher than 43.2% in co-culture group (p＜0.05). These results demonstrated that bovine HBs can be successfully cryopreserved by two-step vitrification method using EFS35.

• Korean Journal of Animal Reproduction
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• v.20 no.1
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• pp.27-34
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• 1996

The objective of this study was to examine the cell number of Total, ICM and TE cells of bovine blastocysts according to development progression cultured in CR1 medium, which was reported as successfully supporting medium for preimplantaion bovine embryo development to the blastocyst stage, by differential labelling of the nuclei with immunosurgery and polynucleot-ide-specific fluorochromes. Blastocysts were obtained at day 8 after in vitro fertilization and classified to early, middle, expanded stage according to the developmental morphology; blastocoel expansion and zona thickness. Also, bias tocysts in the same category were divided into two parts to check the Total cell number by using bisbenzimide only and ICM, TE and Total cell number by using immunosurgery and two polynucleotide-specific fluorochromes. 1) The development rate of blastocysts at day 8 after in vitro fertilization was 29.3% and classified bIas tocysts to early, middle, expanded and hatching stage were 8.7, 9.9, 7.6 and 3.1%, respectively. 2) The numbers of total blastomere using bisbenzimide in the classified blastocysts to early, middie and expanded were 46.9${\pm}$8.6, 66.2${\pm}$12.5 and 122.8 ${\pm}$ 14.4, respectively. This indicated that CR1 is a appropriate culture medium for bovine embryo development. 3) The count of ICM and TE cell number by using differential labelling with immunosurgery and polynucleotide-specific fluorochromes in the classified blastocysts to early, middle and expanded; ICM cell numbers of were 12.8${\pm}$5.9, 26.3${\pm}$8.4 and 35.5${\pm}$15.0, respectively and TE cell numbers were 30.5${\pm}$5.0, 4 41.3${\pm}$8.2 and 81.1${\pm}$13.4, respectively. These results presented that the increase of ICM and TE cell numbers averaged two and three doublings between early and expanded blastocyst stage and also total cell number counted from ICM nuclei and TE nuclei by using differential label-ling showed the increase pattern with development advance level and the results were similar to total cell number obtained from bisbenzimide treatment only. Therefore, the differential labelling of ICM and TE nuclei in situ is a very useful technique to evaluate embryo qualities and can be used as an indicator on study of preim-plantation embryo development.

• Proceedings of the KSAR Conference
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• 2001.03a
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• pp.88-88
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• 2001

소 난포란을 체외에서 성숙, 수정시킨 후, 2~8 세포기 수정란을 체외배양액인 CR$_1$aa에 일정량의 nitric oxide scavenger, Hb와, inhibitor인 L-nitro - L- arginine methyl ester (L-NAME)를 첨가 배양하여 체외발육에 미치는 영향을 검토하고자 실시하였다. 체외수정 후 체외배양 48시간에 난구세포의 제거 유.무에 따라 CR$_1$aa 배양액에 hemoglobin을 0, 1, 5$\mu\textrm{g}$/$m\ell$를 첨가한 구의 상실배기이상 체외발육성적은 난구세포를 제거한 구에서 23.8%, 33.3% 및 26.8%였으며, 난구세포를 제거하지 않은 구에서는 각각 39.5%, 54.8% 및 48.8%로써 난구세포를 제거하지 않은 구에 Hb를 1$\mu\textrm{g}$/$m\ell$를 첨가한 구가 여타구 보다 통계적으로 높은 결과를 얻었다(P<0.05). 체외수정 후 체외배양 96시간 후 난구세포를 제거 유.무에 따라 Hb를 0, 1, 5$\mu\textrm{g}$/$m\ell$를 첨가하였을 때, 상실배기 이상 체외발육성적은 난구세포를 제거한 구에서 각각 28.6%, 46.2% 및 39.1%였으며, 난구세포를 제거하지 않은 구에서는 각각 33.9%, 67.2% 및 46.0%로써, 난구세포를 제거하지 않은 구에 Hb를 1$\mu\textrm{g}$/$m\ell$첨가구가 여타구에 비해 통계적으로 유의하게 높게 나타났다( P<0.05).CR$_1$aa배양액에 L-NAME를 0, 10, 50 및 100mM을 첨가한 구에서 상실배이상 발육된 체외발육성적은 각각 55.6%, 64.9%, 58.8% 및 66.7%로써 L-NAME 첨가구가 무첨가구에 비해 커다란 차이가 나타나지 않았다(P>0.05). 본 실험의 결과로 볼 때, nitric oxide scavenger인 hemoglobin의 첨가는 체외수정 후 체외배양 96시간에 1$\mu\textrm{g}$/$m\ell$ 첨가하는 것이 체외수정란의 체외 발육율을 향상시켰으며, nitric oxide inhibitor인 L-NAME는 첨가 농도에 관계없이 체외수정란의 체외발육율에 영향을 미치지 않는 것으로 나타났다. 본 실험에서 생산된 배반포기 체외수정란의 세포수에는 커다란 차이가 인정되지 않았다.

• Journal of Embryo Transfer
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• v.13 no.3
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• pp.313-321
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• 1998

This study was conducted to investigate the effects of equilibration and dilution methods on the survival rate of vitrified IVM-IVF bovine blastocysts. Vitrification solution was composed with 20% glycerol, 20% ethylene glycol, 3/8 M sucrose and 3/8 M dextrose in D-PBS supplemented with 20% FBS (GESD). Embryos were equilibrated in 1 of 3 methods: 3-step (El), 2-step (E2), or 1-step (E3), and after loading into 0.25-ml straws, were plunged into liquid nitrogen. After warming in water bath at 2$0^{\circ}C$, cryoprotectants were diluted in 1 of 3 methods: 1) D1(VS+1/2 M sucrose, 1/2 M sucrose and l/4 M sucrose), 2) D2 (1/2 M sucrose and 1/4 M sucrose), or 3) D3(1/2 M sucrose only). All procedures except warming were conducted at room temperature. Survival and hatching rates of blastocysts and expanded blastocysts following equilibration methods were 50 and 83.6%, and 27.8 and 67.3%, respectively in El, which were significantly higher (P〈0.01) than those of E2 (16.7 and 23.2%, and 7.4 and 12.5%, respectively) and 23 (0 and 3.7%, and 0 and 0%, respectively). Survival and hatching rates of expanded blastocysts were significantly (P〈0.01) higher than those of blastocysts in El. Survival rates of blastocysts and expanded blastocysts following dilution methods were 52% and 80.6% in D2, which were significantly higher (P〈0.05) than those of D1 (29.6 and 48.3%) and D3 (47.2 and 63.8%). Hatching rates of blastocysts were similar in D1, D2 and D3, however in expanded blastocysts, that of D2(61.3%) was significantly higher (P〈0.01) than that of D1(34.5%). Survival rates of expanded blastocysts in D1 and D2, and hatching rates in D2 and D3 were significantly higher(P〈0.01) than those of blastocysts. These results indicate that the viability of vitrified blastocysts was improved by the several steps of equilibration, and by 2-steps dilution after warming, independently of their stage of development. The results also indicated that the expanded blastocysts are more profitable to vitrification than blastocysts.

• Journal of Embryo Transfer
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• v.19 no.3
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• pp.219-227
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• 2004

This study was conducted to develop a serum-free, defined medium of IVM of pig oocytes. The TCM-199 with supplemented with polyvinylalcohol(PVA), polyvinylpyrrollidone(PVP) and porcine follicular fluid(pFF) were used as basal medium. The effects of the these additives on the rates of maturity and development under in-vitro fertilization and in vitro culture were examined and subsequently considered on the possibilities be sustituted for the bovine serum albumin(BSA). Maturation rate of pig oocytes in IVM media containing PVA(82.4％), pFF(89.4％) and BSA(90.0％) were significantly higher(P<0.05) than that of PVP(78.6％). Cleavage rate after IVF of PVP(64％) was significantly lower(P<0.05) than these of PVA(73％), pFF(77％) and BSA(73％) supplements. in vitro development rates to morulae and blastocyst on PVP(54％) were also significantly lower(P<0.05) than these of the supplements of PVA(63％), pFF(69％) and BSA(65％). In comparison of maturation and fertilization rates of pig oocytes in each supplements, the maturity rates of PVA(82.4％), pFF(89.4％) and BSA(90.0％) were significantly lower(P<0.05) than that of PVP(72.4％) and while, the fertilization rates of pFF(87.1％) and BSA(89.1％) were significantly higher(P<0.05) than these of PVA(78.0％) and PVP(70.6％). It may be concluded that PVA and pFF can be substituted far BSA in medium for culturing pig oocytes; however, it may be considered that PVP were limited to for BSA in the in vitro culture of the embryos.