Direct transfer of equine blastocysts frozen-thawed in the presence of ethylene glycol and sucrose.
Abstract: The present study was designed to examine the suitability of ethylene glycol as a cryoprotectant for equine embryos. Blastocysts recovered nonsurgically from Day 6 donor mares were cryopreserved by conventional 2-step freezing in the presence of 10% ethylene glycol (EG), 10% glycerol (Gly), or 10% ethylene glycol + 0.1M sucrose (EG + Suc). After thawing, the EG and Gly were removed by a 6-step manner, and the EG + Suc was diluted to one fourth in the freezing straw. The postthaw blastocysts were transferred nonsurgically into the uteri of recipient mares on Days 4 to 7 after ovulation. Pregnancy rates, based on Day 15 ultrasonography, were 25.0% (2/8) and 37.5% (3/8) for the blastocysts frozen in EG and Gly, respectively. Direct transfer following thawing and in-straw dilution of blastocysts frozen in EG + Suc resulted in a pregnancy rate of 63.6% (7/11). In fresh Day 6 blastocysts (control group), the pregnancy rate was 70.0% (7/10). These results indicate that the combined use of ethylene glycol and sucrose in a 2-step freezing regimen allows for the direct transfer of frozen-thawed blastocysts into recipient mares, with an acceptable pregnancy rate.
Publication Date: 1996-11-01 PubMed ID: 16727984DOI: 10.1016/s0093-691x(96)00292-0Google Scholar: Lookup
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- Journal Article
Summary
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This research article investigates the use of ethylene glycol and sucrose as cryoprotectants for freezing equine embryos. The study concluded that the use of these substances in a two-step freezing process allows for the successful transfer of these frozen-thawed embryos into recipient mares, with a satisfactory pregnancy rate.
Objective of the Study
- The main objective of the study was to gauge the potential of using ethylene glycol as a cryoprotectant for preserving equine embryos. The researchers also aimed to test the combined use of ethylene glycol and sucrose and evaluate its effectiveness.
Methodology
- The scientists extracted blastocysts non-surgically from Day-6 donor mares for the experiment.
- These were cryopreserved using a traditional 2-step freezing process, incorporating either 10% ethylene glycol, 10% glycerol, or a combination of 10% ethylene glycol with 0.1M sucrose.
- After the thawing process, the solutions of ethylene glycol and glycerol were removed in a 6-step procedure and the combined solution of ethylene glycol and sucrose was diluted by a quarter within the freezing straw.
- The thawed blastocysts were then non-surgically transferred into recipient mares’ uteri between 4 to 7 days post-ovulation.
Results
- The pregnancy rates, verified using ultrasonography at Day 15, were 25.0% (2 out of 8) and 37.5% (3 out of 8) respectively for the blastocysts frozen using ethylene glycol and glycerol.
- A significantly higher pregnancy rate of 63.6% (7 out of 11) was achieved from the direct transfer of blastocysts frozen using the combined solution of ethylene glycol and sucrose following the in-straw dilution process.
- In comparison, the control group which involved the transfer of fresh Day 6 blastocysts presented a pregnancy rate of 70.0% (7 out of 10).
Conclusion
- In conclusion, the study confirmed that using a combination of ethylene glycol and sucrose as part of a 2-step freezing regimen enables the direct transfer of frozen-thawed equine blastocysts into recipient mares with an acceptable pregnancy rate.
Cite This Article
APA
Hochi S, Maruyama K, Oguri N.
(1996).
Direct transfer of equine blastocysts frozen-thawed in the presence of ethylene glycol and sucrose.
Theriogenology, 46(7), 1217-1224.
https://doi.org/10.1016/s0093-691x(96)00292-0 Publication
Researcher Affiliations
- Laboratory of Horse Production, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido 080, Japan.
Citations
This article has been cited 2 times.- do Nascimento AD, Marques JCC, Cezar ARR, Batista AM, Kastelic JP, Câmara DR. Inhibition of Na(+), K(+) -ATPase with ouabain is detrimental to equine blastocysts.. Anim Reprod 2020 Jan 22;17(1).
- Barfield JP, McCue PM, Squires EL, Seidel GE Jr. Effect of dehydration prior to cryopreservation of large equine embryos.. Cryobiology 2009 Aug;59(1):36-41.
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