• Clinical and Experimental Reproductive Medicine
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• v.38 no.4
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• pp.203-209
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• 2011

Objective: This study was performed to compare the efficiency of slow freezing and vitrification based on survival, development to blastocysts, and cell numbers of blastocysts. Changes in embryonic gene expression in fresh and frozen-thawed embryos were also examined. Methods: Eight-cell stage embryos were collected from superovulated female BDF1 mice. The collected embryos were randomly divided into three groups. One group was maintained as fresh controls (n=42), one was frozen by slow freezing (n=43), and one was cooled by vitrification (n=43). After thawing or cooling, survival rates, development to blastocyst, and cell numbers and inner cell mass (ICM) cell numbers of blastocysts were compared with those of the control group. The expressions of eight genes ($Rbm3$, $Birc5$, $Sod1$, $Sod2$, $Cirbp$, $Caspase3$, $Trp53$, $Hsp70.1$) were examined by real time-quantitative polymerase chain reaction in the fresh and frozen-thawed embryos. Results: There were no significant differences in the slow freezing and vitrification groups' survival rate after thawing (88.4% vs. 88.4%), development to blastocyst (100% vs. 97.4%), cell numbers ($107.0{\pm}21.0$ vs. $115.0{\pm}19.7$), or ICM cell numbers of blastocysts ($11.3{\pm}5.2$ vs. $11.1{\pm}3.7$). Cell numbers of blastocysts were significantly ($p$ <0.05) lower in the frozen-thawed embryos than the fresh embryos. There were no significant differences in the slow freezing and the vitrification groups' expressions of the eight genes. The expressions of $CirbP$ and $Hsp70.1$ were higher in the frozen-thawed embryos than in the fresh embryos but there were no significant differences. Conclusion: These results suggest that there were no significant differences between embryos that underwent slow freezing and vitrification.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.5
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• pp.612-616
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• 2004

This study was carried out to compare the semen characteristics, frozen-thawed sperm viability and testosterone concentration and in vitro fertilization (IVF) and development of in vitro matured pig oocytes between two Yorkshire boars. Semen and blood samples were collected once per week from October to November 2002 from two adult Yorkshire boars at 18 months of age with 170 kg body weight. Sperm were deep frozen in 5 ml maxi-straws with lactose-egg yolk and N-acetyl-D-glucosamine (LEN) diluent and stored in liquid nitrogen. Blood samples were obtained at 10 a.m. by inserting a 21 gauge, hypodermic needle attached to 10 ml syringe into surface veins in the ear. The concentration of testosterone was determined by Competitive Enzyme Immunoassay. Ovaries were collected from prepubertal gilts at a local slaughter house. Cumulus oocyte complexes were aspirated from antral follicles (3 to 6 mm in diameter). The medium used for oocyte maturation was modified TCM 199. After about 22 h of culture, oocytes were cultured without cysteamine and hormones for 22 h at $38.5^{\circ}C$, 5% $CO_2$ in air. For IVF, one frozen 5 ml straw was thawed at $52^{\circ}C$in 40 sec and was diluted with 20 ml Beltsville thawing solution at room temperature. Sperm were washed 2 times in mTLP-PVA and inseminated without preincubation after thawing. Oocytes were inseminated with $2{\times}10^7$/ml sperm concentration. Oocytes were coincubated for 6 h in 500 ${\mu}$l mTBM fertilization medium. At 6 h after IVF, oocytes were transferred into 500 ${\mu}$l NCSU-23 culture medium for further culture of 48 and 144 h. There were no significant differences in the semen volume, motility, normal acrosome morphology and sperm concentration of raw semen between A and B of Yorkshire boar. However, motility and normal acrosome of boar A were higher than those of boar B at 0.5, 2, 3, 4, 5 and 6 h incubations of frozen-thawed sperm. Testosterone concentration (3.75 ng/ml) of boar A was higher than that (2.34 ng/ml) of boar B. The rate of blastocyst formation (15.1%) of boar A was higher than that (10.4%) of boar B. In conclusion, serum testosterone concentration of boar showed very important role for the frozen-thawed sperm viability and the blastocyst formation of pig oocytes matured in vitro.

• Korean Journal of Veterinary Research
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• v.27 no.2
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• pp.331-334
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• 1987

The effects of ethylene glycol as a cryoprotective agent on the survival of frozen-thawed mouse embryos were examined. The effects of the stage of development of ethylene glycol were also examined. Eight-cell embryos, morulae, early blastocysts and mid-blastocysts were recovered from superovulated immature ddY mice. Ethylene glycol was added to the embryos in 5 equal increments 5 minutes apart, giving a final concentration of 1.5M. The embryos were cooled to ${-6^{\circ}C}$ at ${1^{\circ}C/min}$ and seeding was induced at ${-6^{\circ}C}$. After being held for a further 5minutes at the seeding temperature, the samples were cooled to ${-35^{\circ}C}$ at ${0.3^{\circ}C/min}$ and then transferred to liquid nitrogen. Rapid thawing was done by placing the straws in ${37^{\circ}C}$ water. The thawed embryos were diluted in PBS of same time and manners as adding procedures. Survival of 8-cell embryos and morulae were assessed as a normal development of the embryos to the blastocyst stage and expanding blastocyst after 54 hours and 48 hours of in vitro culture, respectively. While those of the early and mid-blastocysts were assessed to the expanding blastocyst stage after 24 hours of in vitro culture. The survival rates of 8-cell embryos, morulae, early blastocysts and mid-blastocysts were 73.8%, 74.3%, 87.8% and 77.4%, respectively. Significant difference on the survival rate among the four stages of development was not observed.

• Journal of Embryo Transfer
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• v.28 no.2
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• pp.141-147
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• 2013

The purpose of this study was attempted to new methods in mammalian embryos vitrification. This method was affected to increase of the embryo vitrification efficiency and it would be applied to the field of embryo transfer to recipient by modified loading method of embryo into 0.25 ml plastic straw. The frozen mouse embryos were carried out warmed from two different cell stages (8-cell and blastocyst, respectively) by attachment of an embryo in the vitrification straw (aV) method. All groups were cultured in M-16 medium to determine the development and survivability for 24 h, respectively. Results shown that, the survivability of two different groups were significantly different (94.8% vs. 70.9%). Total cell number was not significantly different the non-frozen blastocyst ($99.7{\pm}12.4$) compared to the post-thaw blastocyst ($94.8{\pm}15.1$). From the 8-cell embryo, total cell number of frozen blastocysts were significantly lower than others groups ($74.7{\pm}14.6$, p<0.05). In the case of cell death analysis, the blastocysts from non-frozen and frozen-thawed 8-cell group were not different ($0.0{\pm}0.0$ vs. $1.9{\pm}3.1$, p>0.05). However, the apoptotic nuclei of blastocyst were significantly observed the frozen-thawed group ($5.4{\pm}4.4$) compared to non-frozen group (p<0.05). Therefore, this new method of embryos using in-straw dilution and direct transfer into other species would be more simple procedure of embryo transfer rather than step-wise dilution method and cryopreservation vessels, so we can be applied in animal as well as human embryo cryopreservation in further.

• Proceedings of the Korean Society of Embryo Transfer Conference
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• 2006.10a
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• pp.113-113
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• 2006

• Journal of Embryo Transfer
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• v.30 no.4
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• pp.271-276
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• 2015

The aim of the study was to investigate the ability of sperm derived from the epididymis in regard to sperm motility, sperm penetration to oocyte and subsequent development of the embryo. Frozen-thawed sperm from epididymis showed similar percentage of motile sperm (VSL ${\geq}25{\mu}m/sec$) as compared to that of commercial sperm (control). Sperm penetration of frozen-thawed epididymal and commercial sperm was not significantly different. Moreover, cleavage and blastocyst rates were similar in both epididymal and control. Sperm derived from the epididymis also showed fertilizability and subsequent embryonic development.

• Journal of Embryo Transfer
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• v.23 no.1
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• pp.1-4
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• 2008

This study was performed to investigate the effect of laser-assisted hole in the zona pellucida (ZP) of frozen-thawed ICR mouse embryos on the process of hatching that is critical for expanded blastocysts to implant into endometrium, Vitrification medium, composed of ethylene glycol and sucrose supplemented with 7.5% (w/v) PVP, was used to freeze $2{\sim}4$ cell stage embryos recovered from oviducts of superovulated and mated female mice before storing them in $LN_2$. Right after thawing them, a laser beam was shot to make a hole in ZP followed by culturing in KSOM for $96{\sim}120\;hr$ and examining development to blastocyst and hatching every 12 hr. Laser-treated embryos showed significantly higher hatching rate compared to control (92.9% vs. 22.1%, p<0.05). From around Day 4, blastocysts developed from laser-treated embryos started hatching while the blastocysts of control group failed to hatch showing a lot of shrinkage. This study shows that a laser-assisted hole in ZP improves the hatching rate of blastocysts developed from frozen-thawed, in vitro cultured ICR mouse embryos.

• Korean Journal of Animal Reproduction
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• v.20 no.2
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• pp.155-161
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• 1996

For a large sclase production of genetically identical or cloned animals, the effect of cryopreservation by vitrification on the post-thaw viability of nuclear transplant rabbit embryos were investigated. The embryos of 16-cell stage were collected from the mated does at 48 hours post-hCG injection, and they were synchronized to G1 phase of 32-cell stage were injected into enucleated recipient cytoplasms by micromanipulation. After culture until 20h post-hCG injection, the nuclear transplant oocytes were electrofused and activated by electrical stimulation. After in vitro culture for 48h, the nuclear transplant embryos developed to morula stage were cryoperserved with EFS solution by vitrification method. The forzen nuclear transplant embryos were thawed and cultured for 72h and the nuclear transplant of blastomeres under a fluorescence microscopy. The in vitro development to blastocyst of intact-fresh and intact-frozen 16-cell embryos was found to be 96.9 and 63.9%, respectively. The in vitro development to blastocyst of nuclear transplant and frozen-thawed nuclear transplant embryos was found to be 74.5 and 42.9%, respectively. Also, their mean blastomere numbers and mean cell cycles/day was 153 and 105, 145 and 1.34, respectively. From the above results it was concluded that the present cryopreservation by vitrification of nuclear transplant rabbit embryos might be useful though was decreased significantly.

• Journal of Embryo Transfer
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• v.12 no.2
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• pp.151-159
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• 1997

In vitro fertilization(IVF) derived morula and blastocyst embryos were bisected by a simple method and cultured in vitro without zona pellucida And also bisected embryos were frozen-thawed and cultured in vitro) to evaluate the survival rate. The results obtained were as follows : The average number of grade I or II immature follicular oocytes recovered by slicing method per ovary was 11.9 from 142 ovaries. Following in vitro fertilization, the rates of cleavage and in vitro development to morula and blatocyst were 61.7 and 32.2% respectively. The successful bisection rate of IVE embryos was 67.51%, and the embryos of blastocyst stage were bisected successfully at significantly(P

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.1
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• pp.7-12
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• 2001

Factors Affecting the Survival of Frozen Thawed Bovine In Vitro Produced Blastocysts. The effect of some factors on the post-thaw survival of a total of 240 in vitro produced bovine blastocysts was investigated using logistic regression analysis. The explanatory variables tested were: type of culture medium before freezing (TCM 199 supplemented with BSA, BSAITS (BSA+insulin+transferrin+selenium), ECS (estrous cow serum) with or without BOEC (bovine oviductal epithelial cells), age of the blastocyst (Day 7, Day 8+9), morphological appearance before freezing (distinct=Q1 or indistinct=Q2 inner cell mass) and type of cryoprotectant (glycerol, 1.0 M or ethylene glycol, 1.6 M). The survival after thawing based on the post-thaw quality and the development after co-culture with BOEC for 24 and 48 hours. Day 7 blastocysts had an almost three times better chance of survival than Day 8+9 blastocysts. Q1, Day 8+9 blastocysts had higher odds to survive after 48 hours in culture than Q2 blastocysts (p<0.05). Blastocysts produced in BSAITS medium had the best chances of survival; however, the odds were not always significant. Blastocysts frozen in glycerol had a better post-thaw quality rating than those frozen in ethylene glycol; however, the difference in post-thaw development at culture was not significant. The relationship between post-thaw quality and post-thaw development at culture was significant (p<0.05). The developmental stage and/or age of the embryo and culture medium where development up to blastocyst takes place affect the post-thaw survival of the bovine embryos.