• Clinical and Experimental Reproductive Medicine
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• 제32권2호
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• pp.177-185
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• 2005

Objective: This study was conducted to find an optimal condition for the vitrification of mouse morulae and expanded blastocysts. Materials and Methods: Mouse embryos were obtained at 2-cell stage and cultured to morula and expanded blastocyst stage in Human Tubal Fluid (HTF) medium supplemented with 10% Serum Substitute Supplement (SSS). The vitrification solutions used were EFS30, EFS35 and EFS40 that contains 30%, 35% and 40% ethylene glycol, respectively, with 18% ficoll and 0.5 M sucrose diluted in Dulbecco's phosphate-buffered saline (DPBS) medium supplemented with 10% SSS. The vitrification procedure was performed in EFS solution with three steps, followed by thawing in 6 steps with 0.5 M sucrose, and then survival and hatching-hatched rate per embryos recovered were compared among six groups. Results: After 24 h culture in different vitrification and thawing solution, the survival rate of morula embryos was 94.1%, 85.4% and 59.7% for EFS30, EFS35 and EFS40 group, respectively. Hatching rate of morula embryos after 72 h culture was 30.6%, 25% and 11.3% for EFS30, EFS35 and EFS40 group, respectively. The survival rate of expanded blastocyst embryos after 24 h culture was 90.4%, 98.5% and 100% for EFS30, EFS35 and EFS40 group, respectively. Hatching rate of expanded blastocyst embryos after 48 h culture was 46.2%, 57.6% and 64.3% for EFS30, EFS35 and EFS40 group, respectively. Conclusion: The EFS30 solution was the best for vitrification of mouse morulae. The EFS40 solution was the best for vitrification of mouse expanded blastocysts. The mouse expanded blastocyst was better than mouse morula for vitrification of mouse embryos.

• Clinical and Experimental Reproductive Medicine
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• 제24권3호
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• pp.325-333
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• 1997

The use of hormonal stimulation in human in vitro fertilization and embryo transfer (IVF-ET) leads to increased production of embryos for ET. So to avoid high pregnancies and to allow conception in future, unstimulated cycles, cryopreservation of spare embryos is desirable. One of the improvement of cryopreservation methods is vitrification. We cryopreserved mouse day 3 embryos by vitrification using the three different vitrification solution (EFS40, VS11 and VS3a). EFS40 solution is consisted of 40% (v/v) ethylene glycol, Ficol170 30% (w/v) and 0.5M sucrose and VS11 is 6.0M ethylene glycol and 1.8M glycerol. And VS3a is 6.5M glycerol and 6% (w/v) BSA (bovine serum albumin). First we tested the toxicity of three vitrification solution by exposure to these solution during 3 min. After washing by thawing solution, the survival rates of each groups are 95.5%, 90.9% and 84.4% (EFS40, VS11 and VS3a). High percentages of them developed to expanded blastocyst and hatching embryos in culture 48hrs 94.2%, 97.7%, 100% and 97.4% (no treatment group, EFS40, VS11 and VS3a). So there is no significant differences among the each group. Second, after thawing of vitirfied embryos, the survival rates of each groups are 96.8% (slow freeze), 94.1% (EFS40), 85.5% (VS11) and 80.0% (VS3a, P vs. no freeze or EFS40 is 0.01). Vitrified embryos exhibited a high rate of development in vitro after 48hrs culture. The percentages of each group to blastocyst and hatching embryos are 88.7% (no freeze), 91.8% (slow freeze), 93.4% (EFS40), 87.7% (VS11) and 73.0% (VS3a, P vs. other group is 0.01). The results suggest that there is no significant differences in exposure of various vitrification solution and day 3 mouse embryos can be vitrified in solution EFS40 and VS11 by simple procedure.

• 한국수정란이식학회지
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• 제8권1호
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• pp.1-7
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• 1993

This study was carried out to investigate the survival rates of late mouse molulae frozen in the state of vitrification and then thawed after equilibrating them separately in EFS 40, GFS 40 and DFS 40 at 1$0^{\circ}C$. The results obtained are as follows : 1. Freezing in the state of vitrification and thawing late mouse molulae after equilibrating them at l0$0^{\circ}C$ in EFS 40 for 30 seconds, one minute and two minutes, we obtained survival rates of 76.7%, 96.7% and 100%, respectively. 2. Freezing and thawing them after equilibrating at 1$0^{\circ}C$ in GFS 40 for 30 seconds, one minute and two minutes, we obtained survival rates of 60%, 96.7% and 10%, respectively. These results are as similar as in the case of EFS 40. 3. Freezing and thawing them after equilibrating at l$0^{\circ}C$ in DFS 40 for 30 seconds and one minute, we obtained survival rates of 62.1% and 0%, respectively. These results represent lower survival rates than those obtained with EFS 40 and GFS 40. In conclusion, even equilibrating late mouse molulae in EFS 40 and GFS 40 at 1$0^{\circ}C$ for more than one minute gives a survival rate of more than 97%, while equilibrating them in DFS 40 at 1$0^{\circ}C$ for more than one minute results in a 0% survival rate, which means that DFS 40 has a strong toxicity.

• 한국수정란이식학회지
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• 제13권1호
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• pp.1-9
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• 1998

In order to improve the cryopreservation by vitrification or slow freezing of nuclear transplant rabbit embryos, the effects of factors affecting embryo cryopreservation such as cryoprotectants, equilibration, cooling rate and post-thaw dilution on post-thaw survial and development were determined using intact embryos of morular stage. And the post-thaw development of nuclear transplanted embryos cryopreserved under the optimal conditions examined was compared between vitrification and slow freezing. The cryoprotectant solution used was ethyleneglycol-ficoll-sucrose (EFS) or ethyleneglycol-poly-vinylpyrrolidone-galactose- I (EPG- I ) for vitrification, and EPG- II for slow freezing. To examine the viability of frozen-thawed embryos, the nuclear transplanted embryos were co-cultured in TCM-199 plus 10% FBS with bovine oviduct epithelial cells(BOEC) for 24 hrs and the intact morulae were co-cultured with BOEC for 5 days and 3 days to hatching blastocyst stage in 39 ˚C 5% $CO_2$ incubator. The results obtained were as follows: Following vitrification with EFS, the post-thaw development of rabbit morulae to hatching blastocyst was significantly(P<0.05) higher in compacted stage(82.4%) than in early morular stage(60.0%). The post-thaw development of compacted morulae to hatching blastocyst was similarly high in vitrification with EFS(82.4%), EPG- I (85.0%) and in slow freezing with EPG- II (83.3%). Following vitrification with EPG- I, the post-thaw development of intact rabbit morulae to hatching blastocyst was similar as 78.0% and 85.0% in 1-step and 2-step post-thaw dilution, respectively. The post-thaw development of nuclear transplanted rabbit embryos of compacted morulae stage to hatching blastocyst was similarly 43.6% and 40.0% in vitrification with EPG- Iand slow freezing with EPG- II, respectively. These results indicated that the rabbit nuclear transplant and intact embryos of morulae stage could be well cryopreserved with either vitrification or slow freezing procedure.

• Clinical and Experimental Reproductive Medicine
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• 제26권3호
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• pp.363-368
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• 1999

연구목적: 본 연구는 동해방지제인 EFS40을 이용한 초자화동결이 생쥐 미성숙란의 cytoskeleton과 염색체의 성상에 미치는 영향을 indirect immunocytochemistry방법과 염색체 분석법으로 알아보고자 실시하였다. 연구재료 및 방법: 본 실험은 생쥐 미성숙란을 EFS40 (40% ethylene glycol, 18% ficou과 0.5 M sucrose가 들어있는 M2배양액)으로 초자화 동결하여 융해한 후 16시간동안 체외 성숙을 유도하여, 제 1극체가 나타난 성숙된 난자를 기준으로 동해제노출군 또는 대조군과 비교 조사하였다. 결과: 초자화동결된 미성숙란의 응해 후 생존율과 체외성숙율은 90.3%과 64.7%로써, 동해제노출군 (86.7%, 69.2%)과 대조군 (100%, 58.3%)에 유사하였다. 초자화동결이 미성숙란의 microtubule과 microfilament에 미치는 영향을 조사하였던 바, 동결군의 microtubule과 micro-filament의 정상적인 형성율 (93.9%, 100.0%)은 동해 제노출군 (94.4%, 100.0%)과 대조군 (100.0%, 100.0%)의 성적과 유사하게 나타났다. 또한, 초자화동결군에서 정상적인 염색체수를 가진 난자의 비율도 65.8%로써, 대조군(79.6%)과 노출군 (69.0%)의 결과와 유의한 차이가 없었다. 결론: 생쥐 미성숙란을 EFS40에 노출하고 동결하는 것이 미성숙란의 cytoskeleton과 염색체성상에 영향을 미치지 않으며, 본 연구에서 사용된 EFS40을 이용한 초자화동결법은 생쥐 미성숙란 동결에 적합하다는 것을 알 수 있었다.

• 한국수정란이식학회지
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• 제14권3호
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• pp.145-153
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• 1999

This study was conducted to investigate the effects of vitrification solution and developmental stage on the survival rate of vitrified-thawed human blastocyst embryos. Human blastocyst embryos were cryopreserved by vitrification using EFS and GE solution, and their survival rates were examined after thawing and further culture. EFS solution was consisted of 40% ethylene glycol, 18% Ficoll 70 and 0.3M sucrose. GE solution was consisted of 25% glycerol and 25% ethylene glycol. Embryos were exposed to EFS and GE solution by 2 steps and 3 steps, respectively, and plunged into liquid nitrogen after loading into 0.25ml plastic straws. Blastocysts were classified into 4 groups in accordance with their developmental stage: into 1) EEB, 2) MEB and 3) EdB, of blastocysts developed on day 5, and 4) 6d-Bla(the blastocysts which formed on day 6). The blastocysts at each stage were vitrified by GE solution and cryopreserved in LN2. After thawing them, we examined their survival rates, respectively. The resulted of this study were as follows: 1. The survival rate of blastocysts vitrified by GE solution was 64.4%, significantly higher than that (5.7%) vitrified by EFS solution (P<0.001). 2. When the blastocysts were vitrified by GE solution according to each developmental stage, the survival rates of EEB, MEB, EdB and 6d-Bla were 65.9%, 65.9%, 73.2% and 58.1%, respectively. In conclusion, the cryopreservation of human blastocysts by vitrification is likely to have a marked advantage in terms of cost, work and time as compared to the conventional slow freezing in IVF-ET programs.

• 한국발생생물학회:학술대회논문집
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• 한국발생생물학회 2003년도 제3회 국제심포지움 및 학술대회
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• pp.113-113
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• 2003

This study was conducted to investigate the effect of vitrification solution(VS) on in vitro developmental competence of immature porcine oocytes. The immature porcine oocytes were exposed to the following vitrification solution, at RT. 1) EFS sol. : 20% ethylene glycol (EG) 3 min, 40% EG + 18%(w/v) Ficoll(MV70, 000) + 0.3 M sucrose 30 sec, 2) GE sol. : 10% glycerol 5 min, 10% G + 20% EG 5 min, 25% G +25% EG 30 sec, 3) EG sol : 1.5M EG 2.5 min, 5.5 M EG + 1.0 M sucrose 30 sec. Oocytes were immediately transferred into 1.0 M, 0.5 M, 0.25 M, 0125 M, 0 M sucrose solution for 2.5 min each at RT. After removal of VS, immature oocytes were matured in vitro and subsequently all oocytes were subjected to IVF followed in vitro culture for 7 days. Maturation rates of oocytes were 38.8%, 44.5%, 22.4% and 57.6%, in EFS, EG, GE and Control, respectively, maturation rates of oocytes in EG and Control was significantly higher than EFS and GE(P<0.01). Fertilization rates of oocytes in Control was significantly higher than other treated groups(P<0.05), but no difference were observed among treated groups. Polyspermic rates were no significant difference among four groups. Cleavage rates of oocytes were 21.9%, 47.1%, 19.0% and 65.9%, in EFS, EG, GE and Control, respectively, cleavage rates of oocytes in EG and Control was significantly higher than EFS and GE(P<0.05), but blastocyst formation rates were no significant difference among four groups. These results suggested that the use of EG solution could be a great challenge for reaching a successful vitrification of immature porcine oocytes.

• Clinical and Experimental Reproductive Medicine
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• 제23권1호
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• pp.41-49
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• 1996

본 연구는 체외수정에 의해 생산된 생쥐 배반포기배를 vitrification 방법으로 동결보존하였을때 높은 생존율을 얻기 위한 적정조건을 검토하고자 실시하였다. 배반포기배를 생산하기 위하여, B6CBA F1 (C57BL/6, (표현불가)${\times}CBA/N$, (표현불가)) 계통의 생쥐 미수정란에 $1{\times}10^6$ spermatozoa/ml 농도의 정자로서 수정을 유도하였으며, 이후 $37^{\circ}C$, 5% $CO_2$배양기내에서 96시간동안 체외배양하였다. 배양 4일째의 배반포기배는 발달상태에 따라 early, middle 그리고 hatching blastocysts로 구분하였다. 본 실험에 사용된 동결보존액은 30% Ficoll과 0.5mol의 sucrose가 첨가된 mDPBS 용액에 40%의 ethylene glycol를 첨가한 EFS 40 (Zhu et al., 1993) 이었고, 수정란은 $25^{\circ}C$의 상온에서 먼저 20% ethylene glycol에 노출된 후 EFS 40 용액으로 옮겨 액체질소에 침지하는 2단계 동결법에 의해 동결보존되었으며, 급속융해하여 다음과 같은 결과를 얻었다. 1. 체외수정율과 배양 4일째 배반포기까지의 배발달율은 각각 89.4%와 86.1%였다. 2. 20% ethylene glycol에서 5분간 평형된 후 EFS 40 용액에 냉동보존된 후 융해된 난자의 생존율은 20% ethylene glycol에 0, 1, 3분간 평형된 난자의 생존율에 비해 유의하게 높았다. 3. 배반포기배를 20% ethylene glycol에서 5분간, EFS 40 용액에 1분간 차례로 노출한 다음 체와배양하였던 바, 배양 24시간째 생존율은 $82.9%{\sim}88.4%$ 였다. 본 연구 결과, 체외수정, 배양된 생쥐 배반포기배는 20% ethylene glycol과 EFS40에 대한 노출만으로는 난자의 생존성에 나쁜 영향을 미치지 않는 것으로 미루어 보아 배반포기배의 초자화 동결이 가능함을 시사하였다. 따라서 동결 융해 후 높은 생존율은 상온에서 난자를 2단계 즉, 20% ethylene glycol에 5분간 평형시킨 후 EFS 40 용액에 노출하여 1분내에 LN2에 직접 침지하는 간편한 동결방법으로 얻을 수 있었다.

• 한국가축번식학회지
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• 제23권1호
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• pp.85-92
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• 1999

본 연구는 동결동결보호제의 종류와 배발달단계가 생쥐의 OPP vitrification 동결방법에 미치는 영향을 알아보고자 실시하였다. 동결속도, 동결보호제 및 배발달단계는 vitrification 방법에 따른 수정란의 생존성에 영향을 미칠 수 있다. 본 연구에 사용된 동결보존액은 40% (v/v) ethylene glycol, 18% (w/v) Ficoll, 0.3 M sucrose와 5% FCS가 첨가된 D-PBS (EFS) 및 16.5% ethylene glycol, 16.5% dimethyl sulfoxide, 0.5 M sucrose 와 5% D-PBS (EDS)을 이용하였다. 배반포기배는 hCG 처리후 90시간째에 자궁으로부터 채취하여 실험 1에 이용하였고, 실험 2와 3에서는 zygote 를 hCG 처리후 18시간에 난관에서 채취하여 mHTF 배양액에 5% $CO_2$, 37$^{\circ}C$ 조건하에 배양하면서 2-, 4-, 8-cell, compacted morula, 또는 blastocyst를 이용하였다. 실험 1에서 배반포기배의 적당한 동결보존액을 결정하기 위하여 EFS 또는 EDS로 OPP vitrification 을 실시하였다. 재확장배반포기에 의한 생존율은 대조군과 EDS 처리군 (100, 100%) 이 EFS 군 (95.0%) 보다 유의적 (P＜0.05)으로 높게 나타났으나, 부화배반포기에서는 EFS 군 (90.0%) 이 대조군 (100%) 및 EDS 군 (95.0%) 보다 유의적으로 낮은 발달율을 보였다. 실험 2에서는 zygote, 2-, 4-, 8-cell, 상실배 빛 배반포기 등의 초기배에서도 OPP vitrification 동결방법이 적당한지를 판단하기 위하여 실시하였다. Zygote (70.0%) 는 동결융해 후 배발달율이 2, 4, 8, 상실배 및 배반포기배에 비하여 유의적으로 낮은 발달율을 보였다 (89.7, 90.0, 92.8, 97.6 및 97.5%) (P＜0.05). 또한 동결융해란의 할구수에서는 대조군 및 배반포기배 (35.7$\pm$2.98 및 39.6$\pm$2.81)에서 zygote, 2-, 4- 8-cell, 상실배 (29.8$\pm$3.21, 31.3$\pm$3.83, 29.3$\pm$3.58, 28.9$\pm$3.21 및 30.8$\pm$2.93) 보다 유의적으로 높게 나타났다 (P＜0.05) 실험 3에서는 zygote의 VS1 에 노출시간에 따른 생존율을 조사한 결과 융해후 2-cell (91.6, 88.5 및 88.9%) 및 배반포기 (83.3, 74.3 및 69.4%) 까지 배발달율은 1,2 및 3분간의 노출시간에 따른 유의적인 차이를 보이지 않았다. 또한 융해후 노출시간에 따른 할구수에서도 유의적인 차이를 보이지 않았다 (36.4$\pm$4.76, 32.4$\pm$4.67 및 27.6$\pm$4.52). 이상의 결과에서 OPP vitrification 방법은 EFS 또는 EDS 동결보존액에 따른 유의적인 차이 없이 이용될 수 있는 것으로 판단된다. 배발달단계에 따른 생존율은 zygote 의 초기배는 2, 4, 8, 상실배 및 배반포기보다 유의적으로 저조한 생존율을 보였다. Zygote의 VS1에 노출시간에 따른 생존율도 1 분간의 노풀시간에서 높은 배발달율을 보였다. OPP vitrification 동결보존방법으로 생쥐수정란의 동결보존에 유용하게 이용가능한 것으로 판단된다.

• 한국가축번식학회지
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• 제21권1호
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• pp.47-52
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• 1997

본 연구는 체외생산된 생쥐 1-세포기배의 초자화동결이 체외/체내 발달율과 수정란 이식후 태어난 산자의 염색체에 미치는 영향을 검토하기 위해 실시하였다. 체외수정하여 얻어진 생쥐 1-세포기배는 EFS40 (40% ethlyene glycol, 30% Ficoll, 0.3 M sucrose) 동결액을 이용하여, 상온 ($25^{\circ}C$)에서 30초 동안 노출한후, 액체질소에 침지하여 초자화동결하였다. 동결후 융해된 생쥐 1-세포기 수정란은 M16 배양액에서 4일동안 배반포기까지 배양하였고, 이때 배반포기까지의 체외배 발달율은 71.5%였으며, 배양된 배반포기배는 가임신 3일된 대리모의 한쪽 또는 양쪽 자궁각에 (6~8개/자궁각) 이식하였다. 모든 대리모는 분만을 유기하였으며, 그 결과를 요약하면 다음과 같다. 임신율과 체내 생존율 즉, 산자 생산(80.0, 39.6%)에 있어서 대조군 (77.8, 50.0%)과 유의차가 없었다. 또한 수정란 이식후 태어난 모든 산자의 염색체 (n=40)는 정상이었다. 이상의 결과로 미루어볼 때 본 실험에서 이용된 초자화동결방법은 생쥐 1-세포기배의 동결에 효과적으로 이용될 수 있음을 시사한다.