• Asian-Australasian Journal of Animal Sciences
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• v.22 no.3
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• pp.343-349
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• 2009

This study was designed to simplify a cryopreservation program for embryonic stem cells (ESCs) by selection of cooling method and cryoprotectant. Commercially available mouse E14 embryonic stem cells (ESCs) were cryopreserved with various protocols, and morphology and viability of the frozen-thawed ESCs and their reactive oxygen species (ROS) production were subsequently monitored. Post-thaw colony-formation of ESCs was detected only after a slow freezing using dimethyl sulfoxide (DMSO) by stepwise placement of a freezing container into a $-80^{\circ}C$ deep freezer and subsequently into -$196^{\circ}C$ liquid nitrogen, while no proliferation was detected after vitrification. When the simplified protocol was employed, the replacement of DMSO with a mixture of DMSO and ethylene glycol (EG) further improved the post-thaw survival. ROS generation in ESCs frozen-thawed with the optimized protocol was not increased compared with non-frozen ESCs. The use of fresh mouse embryonic fibroblasts as feeder cells for post-thaw subculture did not further increase post-thaw cell viability. In conclusion, a simplified slow-freezing program without employing programmable freezer but using DMSO and EG was developed which maintains cell viability and colony-forming activity of ESCs during post-thaw subculture.

• Journal of Korean Society of Forest Science
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• v.98 no.1
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• pp.115-124
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• 2009

New strain needs to maintain desirable characteristics for long term when it was bred, but in lapse of time it degenerates into a bad condition. Therefore the influence of temperature on the viability and survival rates of Lentinula edodes strains were examined after cryopreservation. Also, liquid nitrogen preservation for L. edodes has been proved to be one of the most reliable method. However, a mechanical damage of strain is inevitable during cryopreservation of the fungus because the fungus is very sensitive to stress of cooling rate in the freezing process. So we tried to find out state change of L. edodes with a programmable freezer. L. edodes strains were preserved at $-20^{\circ}C$, $-80^{\circ}C$ and $-196^{\circ}C$ for 50 days. At $-20^{\circ}C$, its mycelial growth became extinct. When thawed, the growth of mycelia which were preserved at $-80^{\circ}C$ was fastest. Attempts were made to investigate viability of L. edodes strains after freezing at $-80^{\circ}C$ and $-196^{\circ}C$, respectively. As the result, more than 90% showed high survival rate of strains tested at $-80^{\circ}C$ and $-196^{\circ}C$. Mycelial growth between apical and basal parts of colony after freezing preservation for 50 days was compared. At apical and basal parts, the survival rates showed 100% at $-80^{\circ}C$, but 98% and 94% at $-196^{\circ}C$, respectively. We confirmed that the ice crystal formation temperatures of L. edodes strains were $-6.0^{\circ}C$ for Sanlim 1, $-5.5^{\circ}C$ for the Sanlim 2, $-4.0^{\circ}C$ for the Sanlim 3 and $-15.5^{\circ}C$ for the Sanzo 302. These results indicated that L. edodes strains showed completely different responses to the ice crystal formation. We knew the fact that even the same species, especially L. edodes, they displayed completely different responses to the same freezing condition. Also, this has nothing to do with the connection between temperature type and freezing point. And a protocol was tried to minimize state change of L. edodes strains using programmable freezer when they are frozen, but it was not effective on them.

• Journal of Veterinary Clinics
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• v.19 no.1
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• pp.73-79
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• 2002

To investigate the usability of frozen canine embryos for embryo transfer in the dog, 19 donors, 3 recipients, and 6 male dogs were used for the experiment. Natural mating or artificial insemination was performed for breeding the bitches in natural estrus. Vaginal smear test along with progesterone titre test were performed to detect the appropriate mating time and the bitches were bred twice during 3-6days following LH surge. Embryo collection was done on 8, 9-11, 12-13 days after the second mating to collect morula and blastocyst. Embryos were frozen using a programmable freezer and preseued in LNE tank. Embryos were thawed in 37$^{\circ}C$ water for 15 seconds and transferred into each uterine horn within 30 minutes. Embryos were collected from 13 bitches of 19 donors(68.4%) and the collected embryos were from between 9 and 13 days after 2nd mating. Embryos were produced both by natural mating(60.0%, 9115) and AI with frozen semen(100.0%, 4/4). Embryos were collected from the donors weighed between 2.5 and 30 kg and their age was from 1.5 to 3 years. 52 embryos were collected from 13 donors and the mean number of embryos was four. The stage of embryos was from 2-cell to gastrula and morulae were colledted mostly from 10 to 11 days after 2nd mating. Embryos were collected evenly from each uterine horn and the rate of embryo collection for the number of corpus luteum was 83.9%. Embryos were transferred to 3 recipients(morula 8, blastocyst 1, gastrula 8), however, no offspring was produced.

• Development and Reproduction
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• v.2 no.1
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• pp.63-68
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• 1998

This study was done to find optimal cryopreservation medium and method to improve the post-thaw motility of human sperm. Thirty three semaen samples were included in the study. Of these, nineteen Samples showing normal semen profile were frozen using three cryprotectants (TYB, TYB+DTT and KS II)to compare post-thaw motility. Fourteen samples were frozen with vapor freezing and programmable freezing methods to compare post-thaw motility in correlation with freezing method. After 24 hrs of cryostorage , the vials were thawed and the post-thaw sperm motility was assessed by two kinds of computer-aededsperm analysis (CASA; SAIS and Hamilton Thorn). As a result, the post-thaw motility of the KS II group was higher than the TYB or TYB+DTT group in normal semen(34.8%, 28.3% and 23.0%, respectively). In the asthenospermia group, a significantly hither post-thaw motility was observed in the KS II (18.5%) compared to those of TYB or TYB+DTT group (13.6%, 10.0%, respectively). No difference was observed between vapor freezing group and computerized freezing group in normal semen (27.8%, 33.2%, respectively) and semen group showing asthenospermia (12.8%, 12.9%, respectively). In conclusion, our results indicate that KS II medium is reliable for cryopreservation of human sperm and vapor freezing and programmable freezing were equally effective in terms of the recovery of motile spermatozoa.

• Journal of Veterinary Clinics
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• v.17 no.1
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• pp.234-237
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• 2000

The dornor, 2 years old, 20kg and mixed breed, was bred naturally on day 1 and day 3 of estrus and eight gastrulae were collected by flushing the uterus of the donor after laparatomy on day 13 after the second mating. The embryos were frozen by programmable freezer and preserved for about 3 months in liquid nitrogen. Another bitch in natural estrus, 2 years old, 30kg, mixed breed, was selected as the recipient and the frozen embryos(8 gastrulae) were thawed and each 4 embryos were transferred into upper partr of left and right uterine horn, respectively, on day 13 after the proper mating day determined by vaginal smear. The ecipient delivered 6 offspring 48 days after embryo transfer. Of 6 puppies, one was still birth and two puppies died one month after birth. Parentage test was performed by DNA analysis using microsatellite sequences for 3 puppiers, the recipient, the donor, the male dog bred with the donor, and the male dog raised near to the recipient. The markers selected for the test were CXX 873(133-157 base pair) and CXX 894(141-165 base pair). Using primers manufactured according to the markers, the blood samples were processed for polymerase chain reaction and the PCR products were treated for electrophoresis. The three puppies showed identical band to that of recipient, consequently, it was concluded that the puppies were offspring of the recipient mated naturally by the male dog, not the offspring by embryo transfer.

• Korean Journal of Plant Tissue Culture
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• v.26 no.4
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• pp.229-233
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• 1999

The possibility for long-term preservation of Larix leptolepis embryogenic tissue was tested in this study. Higher relative increase of the tissue fresh weight was observed when embryogenic tissue was pretreated for 24 hrs in a medium containing 0.4 M sorbitol or 20% polyethyleneglycol with cooling rate of -0.33$^{\circ}C$/min. The fast cooling rate of -0.5$^{\circ}C$ and -1.$0^{\circ}C$/min appeared to be less effective in regrowth of tissues from cryopreservation. No DNA variants have been observed by PCR analysis among the embryogenic tissues recovered after 1-, 7-, and 28-day-cryopreservation. The post-thaw embryogenic tissue gave rise to mature somatic embryos which developed into plants.

• Journal of Embryo Transfer
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• v.23 no.3
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• pp.223-227
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• 2008

The cryopreservation of Hanwoo embryos has become an integral part of assisted reproduction in animal. The objective of this study was to assess the effect of The objectives of this study were: (1) to evaluate the influence of bovine embryo developmental stage on in vitro embryo development after freezing, (2) to study the efficiency compared with conventional freezed embryos at different embryo source. For conventional slow-freezing, day 7 or 8 expanded blastocysts were collected. The standard freezing medium was 1.8 M ethylene glycol (EG). Embryos were equilibrated in 1.8 Methylene glycol(EG) with 0.1 M sucrose in Dulbecco's phosphate-buffered saline (D-PBS) supplemented with 0.5% bovine serum albumin. Embryos were then loaded individually into 0.25 ml-straw and placed directly into cooling chamber of programmable freezer precooled to $-7^{\circ}C$, after 2 min, the straw was seeded, maintained at $-7^{\circ}C$ for 8 min, and then cooled to $-35^{\circ}C$ at $0.3^{\circ}C$/min, plunged and stored in liquid nitrogen for at least 3 days. For thawing, the straw containing embryos were warmed in air for 10 see and exposed to $37^{\circ}C$ water for 20 sec. Straws were then removed from $37^{\circ}C$ water. Rates of blastocyst survive and hatched were evaluated at 12 to 48h post-warming. The re-expansion and hatched rates of morula embryos were significantly lower than those obtained for blastocysts and expansion blastocysts (31.6%, 10.5% vs, 68.9%, 22.2% vs, 73.7%, 53.6%, respectively). No differences in re-expansion rates were found between in vivo and in vitro blastocysts. whereas hatched rates was significantly higher (51.2%) in vivo compared with in vitro embryos (18.6%). in conclusion, demonstrate that conventional freezing can be used successfully in cryopreservation of in vitro and in vivo bovine embryos, and that it might be considered for use in commercial programs and embryo preservation.

• Journal of Embryo Transfer
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• v.29 no.1
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• pp.13-19
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• 2014

This study was carried out to study the survival rate of thawed Hanwoo embryos frozen by the slow-rate freezing or the cryotop vitrification method. Hanwoo cumulus-oocyte complexes were recovered from ovaries at a slaughter house, matured for 20~22 hours, fertilized with Hanwoo semen for 5~6 hours, and cultured for 7~9 days in $38.5^{\circ}C$, 5% $CO_2$ incubator. For freezing, Day 7~9 blastocysts were collected. Embryos for the slow-rate freezing were equilibrated in 1.8 M ethylene glycol (EG) with Dulbecco's phosphate-buffered saline (D-PBS). Programmable cell freezer was precooled down to $-7^{\circ}C$, and the straw was seeded during 8 minutes-holding time, and was cooled to $-35^{\circ}C$ at the cooling rate of $0.3^{\circ}C/min$, and then was plunged and stored in liquid nitrogen. Embryos for the cryotop vitrification were treated in TCM199 with 0.5 M sucrose, 16% EG, 16% dimethylsulfoxide (DMSO). Embryos were then loaded individually onto cryotop and plunged directly into liquid nitrogen. The survival rates of embryos frozen by these two freezing methods were evaluated at 12 to 24h post-thawing. The survival rates of frozen/thawed Hanwoo embryos by the cryotop vitrification method ($56.86{\pm}26.53%$) were slightly higher than those by the slow-rate freezing method ($55.07{\pm}26.43%$) with no significant difference. Using the cryotop vitrification and the slow-rate freezing of Hanwoo blastocysts on Day 7 following in-vitro fertilization (IVF) treatment, the survival rates of frozen/thawed Hanwoo embryos were $72.65{\pm}18.3%$ and $79.06{\pm}17.8%$, respectively. The survival rates by the cryotop vitrification were higher than those by the slow-rate freezing on both Day 8 and 9 with significantly higher survival rate on Day 9 (p<0.05). Using the cryotop vitrification and the slow-rate freezing of Hanwoo embryos to compare between three different blastocyst stages, the survival rates of the blastocyst stage embryos were $66.22{\pm}18.8%$ and $45.76{\pm}12.8%$, respectively with higher survival rate by the vitrification method (p<0.05). And the survival rate of expanded blastocysts was higher than those of early blastocysts and blastocysts in two freezing methods with significantly higher survival rate by the slow-rate freezing method (p<0.05).

• Journal of Animal Science and Technology
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• v.48 no.6
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• pp.797-804
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• 2006

The present study was undertaken to investigate the post-thawed survivability of bovine embryo depending on different dose of ethylene glycol and sucrose. Ovaries were collected at local slaughterhouse and the cumulus-oocyte-complexes aspirated from ovaries were in vitro matured, fertilized and cultured at 39°C in an atmosphere of 5% CO2 incubator. For conventional slow-freezing, d 7 or 8 expanded blastocysts were collected. Embryos were equilibrated in 1.5 M and 1.8 M ethylene glycol(EG) with 0.1 M and 0.3 M sucrose in Dulbecco's phosphate-buffered saline(D-PBS) supplemented with 0.5% bovine serum albumin. Embryos were then loaded individually into 0.25ml-straw and placed directly into cooling chamber of programmable freezer precooled to 󰠏7°C, after 2 min, the straw was seeded, maintained at 󰠏7°C for 8 min, and then cooled to 󰠏35°C at 0.3°C/min, plunged and stored in liquid nitrogen for at least 3 days. For thawing, the straw containing embryos were warmed in air for 10 sec and exposed to 37°C water for 20 sec. Straws were then removed from 37°C water. Rates of blastocyst survive and hatching were evaluated at 24 to 72 h post-warming. No difference of the survivability was shown between 1.5 M and 1.8 M EG (71 and 70%, respectively). Addition of 0.1 M sucrose to 1.5 M and 1.8 M ethylene glycol in the freezing solution did not differ significantly embryo survival (74 and 77%, respectively), whereas survival rates was higher(89%) in freezing solution contained 0.3M sucrose to 1.8M EG compared with 0.3M sucrose to 1.5M EG group(71%). However, there was no difference in the overall total cell number between the two groups (122±1.8 vs 131±1.4, respectively). In conclusion, the results suggest that 0.3 M sucrose in 1.8 M EG may be optimal condition for freezing and thawing methods with in vitro produced embryos and may be applied to on-farm conditions for embryo transfer.

• Journal of Embryo Transfer
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• v.18 no.1
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• pp.43-50
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• 2003

The objective of this study was to investigate the effect of cryopreservation by slow and rapid freezing on the sperm motility index, viability and morphology of post-thaw human spermatozoa. After rapid freezing and thawing, sperm motility index was significantly higher (MOT:47.40$\pm$20.06%, VCL : 38.12$\pm$15.58 $\mu$m/s, VSL : 28.19$\pm$14.10 $\mu$m/s, VAP:33.64$\pm$15.15 $\mu$m/s, and HYP 2.77$\pm$2.71%) than slow freezing and thawing(MOT : 43.39$\pm$ 18.79%, VCL .33.91 $\pm$ 13.50 Um/s, VSL . 19.98$\pm$0.88 $\mu$m/s, VAP : 24.60$\pm$11.72 $\mu$m/s, and HYP . 1.33$\pm$1.57% ; P<0.05). But sperm Linearity(LIN) was significantly lower(28.83 $\pm$ 10.35) comparing to the slow freezing method(34.64 $\pm$ 11.36 ; P<0.05). On the other hand, significant difference were not observed MAD, WOB, DNC and DNM by slow and rapid frozen-thawed methods. After rapid freezing and thawing, sperm viability was lower(60 $\pm$ 2.2%) than slow freezing method(62 $\pm$2.1%) and sperm morphology was higher(46$\pm$7.7%) than that(44: 8.3). But there was no significantly These results indicate that rapid freezing method was positive effect of sperm cryopreservation in human.