• Clinical and Experimental Reproductive Medicine
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• v.32 no.2
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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.

• Journal of Embryo Transfer
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• v.8 no.1
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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.

• Korean Journal of Animal Reproduction
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• v.21 no.2
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• pp.131-137
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• 1997

This study was carried out to investigate the in vivo development rates of vitrified-thawed mouse expanding, hatching and hatched blastoc ysts(BL). In vitro fertilization produced blastocysts were vitrified in EFS40(40% ethylene glycol, 30% Ficoll and 0.3 M sucrose in phosphate buffer saline containing 10% FBS). Expanding a and hatching blastocysts were equilibrated in 20% ethylene glyco](EG) for 5 min. before exposure to EFS40 at 25°C for 1 min., they were then vitrified in liquid nitrogen. Hatched blastocysts which cultured in m-CR1 medium supple mented 0.4% bovine serum albumin on day 5. were equilibrated in 10% EG for 5 min. and then vitrified in EFS40 for 30 sec. After thawing, re-expanding blastocysts were transferred to recipients(3 day of pseudopregnant) on one or both uterine horns(6-8 embryos per a horn). Preg¬n nancy rates of recipients and implantation were a assccessed by autopsy on 15 gestation. The res¬u ults obtained in these experiments were summar¬1 ized as follows; 1) The pregnancy and live fetus rates, for vitrified expanding BL(77.8 and 25.0%) and hatching BL(77.8 and 26.4%)n vitro were not significantly difference in those of control BL (66.7 and 42.9%: 83.3 and 40.4%), respectively, 2) in vitro development of vitrified hatched BL was 34.0%. and 3) in vivo developmental rate of vitrified hatched BL was only 33.3%. These results suggested that proposed rapid vitrification p procedures used EFS40 cryoprotectant can be effectively performed in mouse expanding Ihatching blastocysts and that mouse blastocysts a after being hatched from zona pellucida can be successfully cryopreserved.

• Clinical and Experimental Reproductive Medicine
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• v.25 no.1
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• pp.71-76
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• 1998

This study was carried out to examine whether the developmental capacity of bovine immature oocytes frozen ultra-rapidly using electron microscope (EM) grids and EFS30 can be obtained. As freezing solution, we used EFS30 which consisted of 30% ethylene glycol, 0.5 M sucrose, 18% ficoll and 10% FBS added in D-PBS. As criterior of oocyte viability, the rates of maturation, fertilization and embryonic development were determined. The results obtained in this experiment were summarized as follows: When ultra-rapidly frozen immature oocytes were thawed, 43.2% of them were survived. The rates of maturation (84.1%) and normal 2 pronuclei formation (57.5%) of frozen immature oocytes were not significantly different when compared to those of control (92.5, 65.0%). In addition, the rates of $\geq2$-cell (65.0%) and blastocyst formation (30.8%) of freezing group were not significantly different when compared to those of control (73.7, 35.7%). These results demonstrate that developmental capacity of frozen-thawed bovine immature oocytes can be successfully obtained when survived from the ultra-rapid freezing method using EM grid and EFS30.

• Clinical and Experimental Reproductive Medicine
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• v.24 no.3
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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.

• Clinical and Experimental Reproductive Medicine
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• v.25 no.1
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• pp.87-92
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• 1998

This study was carried out to investigate in vitro/in vivo development of vitrified mouse oocytes. Mouse oocytes were vitrified using EFS30, 35 and 40 (30, 35 and 40% ethylene glycol, 18% ficoll and 0.5 M sucrose in M2 medium). After being exposed or vitrified-thawed, oocytes of normal morphology were inseminated in vitro by $1-2\times10^6/ml$ of epididymal sperm. The rates of fertilization, in vitro/in vivo development and cell number (inner cell mass and tropectoderm cell) of blastocysts in each treatment group were examined. The results obtained in these experiments were summarized as follows: The cleavage rates were obtained in EFS35 containing 35% ethylene glycol higher than in EFS30 and EFS40. The development rate of vitrified-thawed oocytes to two-cell stage after in vitro fertilization (51.1%) was significantly different compared to that of exposed to vitrification solution without cooling (60.0%) and control (68.2%) (p<0.05). However, there were no differences in the blastocyst formation from the cleaved embryos among groups (75.0, 73.3 and 80.0%). Also, the mean number of cells per blastocysts of vitrified group $(92.5{\pm}2.9)$ was similar to that of the exposed $(98.5{\pm}5.3)$ and control $(100.9{\pm}4.8)$. In vivo development of the blastocysts derived from vitrified-thawed oocytes resulted in fetal development (50.7%) and implantation rates (80.0%) which are very similar to those of control (58.2, 78.2%). These results suggest that mouse oocytes could be cryopreserved using vitrification solution (EFS35) based on ethylene glycol.

• Proceedings of the Korean Society of Developmental Biology Conference
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• 2003.10a
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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.

• Korean Journal of Animal Reproduction
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• v.22 no.2
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• pp.171-176
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• 1998

This study was carried out to confirm whether the in vivo developmental potential of mouse hatched blastocysts (HBs) can be obtained by vitrification method using the cryoprotectant EFS35. The HBs ($\theta$ 130$\mu\textrm{m}$) were cultured in vitro until day 5 from zygotes produced in vivo and were equilibrated in 10% ethylene glycol(EG) for 5 min, and then were exposed or vitrified in EFS35 (35% EG, 18% Ficoll and 0.3M sucrose). After 30 min thawing, re-expanding HBs were transferred into one or both uterine horns of pseudopregnant recipients on day 3 (4~6 embryos /horn). Pregnancy rates of recipients and implantation were assessed by autopsy on day 15 of gestation. The results obtained in these experiments were summarized as follows : After thaw-ing, in vitro survival of HBs was not significantly different between exposed (65.5%) and vitrified(54.5%) group. Also, when the in vivo development potential was examined, total implantation was not different between control (58.5% ) and vitrified (41.0%) group, although the live fetus formation of vitrified group (24.0%) was significantly lower than that of control (58.3%) group (p< 0.05). These results suggested that vitrification freezing method of mouse HBs using EFS35 can be used to make wide the utility of embryo transfer of the more embryos produced in vitro.

• The Korean Journal of Physiology and Pharmacology
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• v.7 no.3
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• pp.169-174
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• 2003

${\gamma}$-Aminobutyric acid (GABA) has been reported to enhance exocrine secretion evoked not only by secretagogues but also by intrinsic neuronal excitation in the pancreas. The pancreas contains cholinergic neurons abundantly that exert a stimulatory role in exocrine secretion. This study was undertaken to examine effects of GABA on an action of cholinergic neurons in exocrine secretion of the pancreas. Intrinsic neurons were excited by electrical field stimulation (EFS; 15 V, 2 msec, 8 Hz, 45 min) in the isolated, perfused rat pancreas. Tetrodotoxin or atropine was used to block neuronal or cholinergic action. Acetylcholine was infused to mimic cholinergic excitation. GABA $(30{\mu}M)$ and muscimol $(10{\mu}M)$, given intra-arterially, did not change spontaneous secretion but enhanced cholecystokinin (CCK; 10 pM)-induced secretions of fluid and amylase. GABA (3, 10, $30{\mu}M$) further elevated EFS-evoked secretions of fluid and amylase dose-dependently. GABA (10, 30, $100{\mu}M$) also further increased acetylcholine $(5{\mu}M)$-induced secretions of fluid and amylase in a dose-dependent manner. Bicuculline $(10{\mu}M)$ effectively blocked the enhancing effects of GABA $(30{\mu}M)$ on the pancreatic secretions evoked by either EFS or CCK. Both atropine $(2{\mu}M)$ and tetrodotoxin $(1{\mu}M)$ markedly reduced the GABA $(10{\mu}M)$-enhanced EFS- or CCK-induced pancreatic secretions. The results indicate that GABA enhances intrinsic cholinergic neuronal action on exocrine secretion via the $GABA_A$ receptors in the rat pancreas.

• Clinical and Experimental Reproductive Medicine
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• v.25 no.2
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• pp.129-134
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• 1998

The objective of this study was to test whether the developmental capacity of human multi-pronuclear (PN) zygotes after ultra-rapid freezing using EM grid can be maintained. For this experiment, multi-PN zygotes which produced in human IVF program were used as an alternatives of normal 2PN zygotes, and they were separated into 3PN or $\geq4PN$ zygotes to compare their in vitro development and cryoinjury according to PN number. As freezing solution, EFS30 which consisted of 30% ethylene glycol, 18% bcoll, 0.5 M sucrose and 10% FBS added D-PBS was used. The result obtained in this experiment was summarized as follows; When the multi..PN zygotes were ultrarapidly frozen and thawed, the high mean percentages (85.5%) were survived. Also when the cleavage rates between control and freezing group were compared with PN number, there were not significantly different in each group (3PN; 81.3% & 85.4% and $\geq4PN$; 90.0% & 95.7%). When the in vitro development rates after thawing were examined, freezing 3PN group (22.0%) was not differed to control 3PN group (38.5%), although the development result of freezing $\geq4PN$ group (45%) was significantly lower than that of control $\geq4PN$ group (44.4%) (p<0.05). These results demonstrate that developmental capacity of human zygote can be obtained by ultra-rapid freezing method using EM grid and EFS30.