• 한국수정란이식학회지
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• 제7권2호
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• pp.81-88
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• 1992

Cryopreservation of mouse embryos biopsied at 4-cell stage was investigated by ultrarapid freezing. Four-cell embryos were obtained from ICR mice on 55h after hCG injection. Zona pellucida of the embryos were partially dissected with a cutting pipet, and then single blastomeres were biopsied from the embryos followed by incubation in $Ca^2$+ and $Mg^2$+-free M16 medium for 30min. Biopsied embryos cultured for lh or 15h were frozen by ultrarapid freezing method using 3M DMSO or 5M glycerol as a cryoprotectant, respectively. The developmental rate of biopsied embryos after ultrarapid freezing and thawing to blastocysts was 81 % in the group of biopsied embryos cultured for lb and 98% in the group of biopsied embryos cultured for 15h, respectively. When biopsied embryos after ultrarapid freezing and thawing were transferred to the uteri of pseudopregnant recipients, normal live young were born. These results suggest that this freezing method can efficiently cryopreserve biopsied mouse embryos.

• Clinical and Experimental Reproductive Medicine
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• 제27권3호
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• pp.283-289
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• 2000

Objective: The study was performed to compare the survival rate and the development of day 2 mouse embryos which had freezing procedures done. Methods: We used three different vitrification solutions (EFS, VS14, DPS) and a ultrarapid freezing solution (UFS) for cryopreservation of day 2 mouse embryo. Results: We tested toxicity by exposing embryos to vitirification solutions and a ultrarapid freezing solution. The survival rates are 100%, 97.8%, 95.6% and 100% (EFS, VS14, DPS and UFS). After cultured for 96 hours, hatching rates of each group are 93.5% (no freezing), 95.6% (EFS), 86.4% (VS14), 93.0% (DPS), and 93.0% (UFS). There is no significant differences among groups. The survival rates after thawing cryopreserved embryos are 80.2%, 91.7%, 69.5%, 0% and 91.8% (slow freezing, EFS, VS14, DPS and UFS). Also cultured for 96 hours, the hatching rates are 93.5% (no freezing), 84.1% (slow freezing), 93.9% (EFS), 48.5% (VS14) and 70.1% (UFS). Conclusion: The survival rates of vitrification in EFS solution and ultrarapid freezing are higher than slow freezing (p<0.05). The hatching rate of vitrification in EFS solution cultured for 96 hours is highest, so vitrification of day 2 mouse embryos in EFS solution considered as more effective for cryopreservation.

• 한국가축번식학회지
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• 제16권3호
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• pp.217-224
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• 1992

These studies were carried out ot investigate on the transferred embryo development following ultrarapid frozen for 8-cell and morula of in vitro fertilization mouse embryos. The post-thaw embryo survival was evaluated and compared by cell stage of embryos and by equilibration time before ultrarapid freezing. The results obatined were summerized as follows: 1. The effects of equilibration time of 3 vs. 6 minutes before ultrarapid freezing and after thawing on the morphological survival and the viability of 8-cell and morulas embryos were not significant. 2. When the ultrarapid frozen-thawed 32 eight-cell and 33 morula embryos, and 30 fresh blastocysts were transferred to pseudopregnant recipient mice, the number of normal offsprings produced were 9(28.1%), 14(42.4%) and 18(60.0%), respectively. From the above resutls, it was concluded that the optimal conditions of pH osmolality of the media for mouse IVF and embryo culture, and the period of sperm preincubation might be 7.1, 310 mOsm and 120 min., respectively,a nd somewhat high conception rate might be resulted from transfer of frozen embryos of morula stage and fresh embryos of blastocyst stage.

• 한국수정란이식학회지
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• 제11권1호
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• pp.35-40
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• 1996

This study was carried out to select the best cryoprotectant and to establish optimal concentration of the cryoprotectant in ultrarapid freezing of mouse 4-cell embryos and morulae, respectively. We investigated survival of ultrarapid frozen embryos according to various cryoprotectants such as glycerol, ethylene glycol, propylene glycol and dimethyl sulfoxide (DMSO). Suvival of the embryos frozen at different concentrations (3.0, 4.0 and 5.0 M) of indivisual cryoprotectant was also tested. Preimplantation developmental rate (96.3%, 83/86) of 4-cell mouse embryos treated with 4.0 M ethylene glycol after ultrarapid freezing and thawing was higher than those of other cryoprotectants (glycerol, propylene glycol and DMSO). In the ultrarapid freezing of mouse morulae, the highest developmental rate (98.8%, 89 /90) of the embryos to blastocysts was shown in the group of 5.0 M glycerol. Thus, these results demonstrate that 4.0 M ethylene glycol and 5.0 M glycerol are optimal for ultrarapid freezing of 4-cell mouse embryos and morulae, respectively.

• 한국가축번식학회지
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• 제17권3호
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• pp.201-207
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• 1993

We determined whether the ultrarapid freezing method is applicable to micromanipulated mouse embryos. One-cell mouse embryos were microinjected with MThGH gene. Nuclei from one-cell embryos of F1(C57BL$\times$CBA) mice were transplanted into enucleated one-cell embryos of ICR mice. The injected and nucleated embryos that developed to 2-cell stage were cryopreserved by ultrarapidfreezing. The embryos equilibrated in freezing medium(3 M DMSO＋0.25 M sucrose＋2% FBS in PBS) were directly immersed into liquid nitrogen and then thawed in 37$^{\circ}C$ water. Development rates of the microinjected and nuclear-transplanted embryos to blastocyst stage after ultrarapidly freezing and thawing were 31% and 55%, respectively. The frozen-thawed embryos were transferred to pseudopregnant recipient, which then gave birth to 17 offsprings. Twelve(14% of the transferred embryos) and five(20%) offsprings were derived from microinjected and nuclear-transplanted embryos, respectively. The results indicate that the DNA injected and nuclear-transplanted mouse embryos are cryopreservable at 2-cell stage by ultrarapid freezing method.

• Clinical and Experimental Reproductive Medicine
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• 제25권3호
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• pp.261-268
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• 1998

The present study was to assess the effect of ultrarapid freezing on the development of 1-cell mouse zygote using cryoprotectants, DMSO (dimethyl sulfoxide) or PROH (1,2-propanediol). We investigated the effect of the type and concentration of cryoprotectant, and of the temperature and time of prefreezing equilibration on their capacity to develop to the blastocyst stage in vitro. The concenration, the equilibration temperature, and the exposure time seemed to serve as an important factor in ultrarapid freezing of 1-cell mouse zygotes. In addition to the exposure time and the concentration of cryoprotectant appeared to playa key role in the development of the embryo. In general, the development of the embryo was more effective at $3^{\circ}C$ than $23^{\circ}C$ and 4.5 M than 3 M for 3 to 5 minutes. At $23^{\circ}C$ the development of the embryo was stimulated by DMSO while at $3^{\circ}C$ it was stimulated by PROH. Thus it has been suggested that there exists a correlation between the concentration of cryoprotectants and exposure time in the development of the embryo. In conclusion, we found that for ultrarapid freezing of mouse 1-cell embryos in DMSO, or PROH-based solution, viability shown optimum depending on the cryoprotectant, the concentration of the cryoprotectant and on the temperature and the duration of equilibration.

• 한국가축번식학회지
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• 제15권2호
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• pp.141-147
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• 1991

This stduy was carried out in order to investigate the effects of cryoprotective concentration and equilibration time on survival rate of ultrarapidly frozen in vitro fertilized bovine embryos. In vitro fertilized bovine embryos, following dehydration by cryoprotective agents and sucorese were directly plunged into liquid nitrogen and thawed in 38$^{\circ}C$ water. Survival rate was defined by development rate to the morula and blaqstocyst stage after in vitro culture of by FDA test. The results are summarized as follows : 1. The survival rates of in vitro fertilized bovine embryos after ultrarapid frozen-thawing in the freezing medium of 0.25M sucroese added 2.0M, 2.5M, 3.0M, 3.5M, 4.0M glycerol were 75.0%, 72.0%, 67.6%, 44.8% and 18.3% respectively. 2. The survival rates of in vitro fertilized bovine embryos after ultrarapid frozen-thawing in the freezing medium of 0.25M sucrose added 2.0M, 2.5M, 3.0M, 3.5M, 4.0M DMSO were 64.0%, 66.7%, 70.8%, 52.7% and 18.6, respectively. 3. The survival rates of in vitro fertilized bovine embryos after ultrarapid frozen-thawing in the freezing medium of 0.25M sucrose added 2.0M, 2.5M, 3.0M, 3.5M, 4.0M propanediol were 68.4%, 64.9%, 63.2%, 62.2% and 34.7%, respectively. 4. The survival rates of in vitro fertilized bovine embryos after ultrarapid frozen-thawing in the freezing medium of 2.50M glycerol added 0.1M, 0.25M, 0.5M, 0.75M, sucrose were 60.5%, 72.2%, 70.1% and 54.9%, respectively. The survival rate of in vitro fertilized embryos after ultrarapid frozen-thawing in the freezing medium of 2.5M glycerol added 0.25M sucrose were higher than concentration of 0.10M, 0.50M and 0.75M sucrose. 5. The equilibration time on the survival rate of in vitro fertilized bovine embryos was attained after short period of time(2.5~5min.) in the freezing medium added 0.25M sucrose and 3.0M DMSO higher than long period time(1~20min.).

• 한국수정란이식학회지
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• 제10권3호
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• pp.203-208
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• 1995

This study was carried out to efficiently use the ultrarapid freezing method in the cryopreservation of mouse ova. For this, the effects of dehydration method, oval vigour and $0^{\circ}C$ controlling method on post-thawing viability were investigated. Fresh mouse ova were dehydrated in mPBS with 3.5M DMSO and /or 0.25M sucrose, and directly immersed in L$N_2$ for ultrarapidly freezing. The frozen ova were thawed at 37$^{\circ}C$, rehydrated in mPBS with 0.25M sucrose, and then repeatedly washed in HAM's Fl0 before evaluating the morphological normality of frozen-thawed ova. The results obtained showed that there was difference between treatments in a experiment. 1) The post-thawing viability of ova dehydrated in multi-step (48.4$\pm$13.8%) was higher than that of ova in two-step (40.9$\pm$14.0%). 2) The post-thawing viability of fertilized ova (87$\pm$14.0%) was significantly(p<0.0l) higher than that of unfertilized ova (5.4$\pm$5.4%). 3) The post-thawing viability of ova dehydrated and rehydrated using a cooling machine (95.8$\pm$4.2%) was significantly(p<0.05) higher than that on ice(84.1$\pm$9.9). In conclusion, in order to efficiently cryopreserve ova in vitro with ultrarapidly freezing method, highly viable embryos should be selected, heavy osmotic shock to the dehydrating ova should be avoided, and embryos in high osmotic condition were dehydrated and rehydrated in a constantly low temperature.

• 한국가축번식학회지
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• 제15권2호
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• pp.133-139
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• 1991

This stduy was carried out in order to investigate the effects of concentration and equilibration time of cryoprotective agents on survival rate of slow and ultrarapidly frozen in vitro fertilized bovine embryos. In vitro fertilized bovine embryos, following dehydration by cryoprotective agents and sucrose, were slowly freezed(from 2$0^{\circ}C$ to -7$^{\circ}C$/-1$^{\circ}C$/min., from -7$^{\circ}C$ -35$^{\circ}C$/-0.2$^{\circ}C$/min. from -35$^{\circ}C$ to -38$^{\circ}C$/-0.3$^{\circ}C$/min.) by cell freezer and directly plunged into liquid nitrogen and thawed in 38$^{\circ}C$ water. Survival rate was defined by development rate to the morula and blastocyst stage after in vitro cultured and FDA test. The results are summarized as follows : 1. The survival rates of in vitro fertilized bovine embryos after slow frozen-thawing in the freezing medium of 0.25M sucrose added 2.5M glycerol, 3.0M DMSO, 2.0M propanediol and 2.5M glycerol＋2.0M propanediol were 84.3%, 85.9%, 77.8%, 74.3%, respectively. 2. The survival rates of in vitro fertilized bovine embryos after slow frozen-thawing in the freezing of 0.50M sucrose added 2.5M glycerol, 3.0M DMSO, 2.0M propanediol and 2.5M glycerol＋2.0M propanediol were 83.8%, 85.1%, 71.4%, 74.6%, respectively. 3. The survival rates of in vitro fertilized bovine embryos after ultrarapid frozen-thawing in the freezing of 0.25M sucrose added 2.5M glycerol, 3.0M DMSO, 2.0M propanediol and 2.5M glycerol＋3.0M propanediol were 69.3%, 70.8%, 63.2%, 67.1%, respectively. 4. The survival rates of in vitro fertilized bovine embryos after ultrarapid frozen-thawing in the freezing of 0.25M sucrose added 2.5M glycerol, 3.0M DMSO, 2.0M propanediol and 2.5M glycerol＋2.0M propanediol were 69.4%, 70.1%, 62.3%, 63.5%, respectively. 5. The survival rates of in vitro fertilized bovine embryos after slow and ultrarapid fromthawing in the freezing medium of sucrose added cryoprotective agents were not significant difference between 5min. and 10min. of equilibration time.

• 한국수정란이식학회지
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• 제30권3호
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• pp.207-211
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• 2015

미세주입법에 의한 형질전환 마우스 제작에는 대량의 전핵기란을 필요로 한다. 본 실험에서는 심플한 형질전환 마우스 제작방법을 확립하기 위해 초급속 동결한 전핵기란을 공시했다. 초급속 동결법으로 동결한 전핵기 체외수정란 139개를 융해 후 공시하고, ${\beta}-actin/luc^+$ 융합유전자를 미세주입하였다. 주입 조작 후, 형태학적으로 정상적인 수정란 101개(72.6%)를 5마리의 수란암컷 마우스에 이식하였다. 그 결과, 이식한 모든 마우스가 임신하고, 최종적으로 15마리(14.8%)의 산자가 태어났다. 한편, 450개의 체외수정란에 대해 동일한 배아조작 후에 338개(75.1%)가 생존하고 14마리의 수란암컷 마우스에 이식 하였다. 그 중에 78%의 수정암컷 마우스가 임신하고, 54마리(19.1%)의 산자가 태어났다. 태어난 산자에 대해서는 southern blot 법에 의해 염색체 내의 도입유전자의 도입을 확인한 결과, 동결수정란 처리구와 체외수정란구에서 각각 6.6%(1/15), 5.5% (3/54)의 마우스에서 도입유전자의 도입이 확인되었다. 더욱이 두 처리구 전부의 형질전환 마우스의 미부조직에서 도입유전자인 루시페라제 유전자의 발현이 관찰되었다. 이상의 결과에 의해 체외수정란 초급속 동결보존법을 사용한 Tg 마우스 제작방법의 확립을 확인하였고, 이러한 결과들로부터 실험기간의 단축과 작업의 간소화에 크게 이바지할 것으로 사료된다.