{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,29]],"date-time":"2026-08-29T00:40:10Z","timestamp":1787964010434,"version":"build-2784847793"},"reference-count":52,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2024,4,10]],"date-time":"2024-04-10T00:00:00Z","timestamp":1712707200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100003725","name":"National Research Foundation of Korea","doi-asserted-by":"publisher","award":["2020R1A2C2008276"],"award-info":[{"award-number":["2020R1A2C2008276"]}],"id":[{"id":"10.13039\/501100003725","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100003725","name":"National Research Foundation of Korea","doi-asserted-by":"publisher","award":["2021R1C1C2013954"],"award-info":[{"award-number":["2021R1C1C2013954"]}],"id":[{"id":"10.13039\/501100003725","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100003668","name":"Korea Institute of Planning and Evaluation for Technology in Food, Agriculture, Forestry and Fisheries","doi-asserted-by":"publisher","award":["320005-4"],"award-info":[{"award-number":["320005-4"]}],"id":[{"id":"10.13039\/501100003668","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100003624","name":"Ministry of Agriculture, Food and Rural Affairs","doi-asserted-by":"publisher","id":[{"id":"10.13039\/501100003624","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Vet. Sci."],"abstract":"<jats:sec><jats:title>Introduction<\/jats:title><jats:p>Embryo cryopreservation is a valuable technique used for preserving genetic resources for long periods. However, the survival rate of embryos is dependent on the method used. Therefore, in this study, we evaluated the efficiency of slow freezing method but with an additional dehydration step prior to freezing to overcome the formation of ice crystals.<\/jats:p><\/jats:sec><jats:sec><jats:title>Methods<\/jats:title><jats:p>Oocytes collected from the ovaries of native Korean cattle subjected to <jats:italic>in vitro<\/jats:italic> fertilization were cultured for 7\u2009days until the formation of expanded blastocysts. Before freezing, the blastocysts were placed in four pre-equilibration media: a control medium with no addition of sucrose, and three experimental media with the addition of 0.1, 0.25, and 0.5\u2009M sucrose, respectively. Then, the pre-equilibrated embryos were frozen. Embryo survival and hatching rates were evaluated morphologically at 24, 48, and 72\u2009h after thawing. Immunofluorescence staining, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay, and gene expression analysis of the re-expanded blastocytes were examined 24\u2009h after freeze\u2013thawing.<\/jats:p><\/jats:sec><jats:sec><jats:title>Results<\/jats:title><jats:p>The survival rate was significantly higher in the 0.1\u2009M group than in the control group (<jats:italic>p<\/jats:italic>\u2009&amp;lt;\u20090.05), and the hatching rate at 72\u2009h was significantly higher in the 0.25 and 0.5\u2009M groups than in the control group (<jats:italic>p<\/jats:italic>\u2009&amp;lt;\u20090.05). TUNEL-positive cells were significantly lower in the 0.25\u2009M group than in the control group (12.5\u2009\u00b1\u20090.9 vs. 8.3\u2009\u00b1\u20090.8; <jats:italic>p<\/jats:italic>\u2009&amp;lt;\u20090.05). The gene expression of <jats:italic>BCL2<\/jats:italic> associated X, heat shock protein 70\u2009kDa, and aquaporin 3 in the 0.25\u2009M group was significantly lower than that in the control group (<jats:italic>p<\/jats:italic>\u2009&amp;lt;\u20090.05).<\/jats:p><\/jats:sec><jats:sec><jats:title>Conclusion<\/jats:title><jats:p>Our study revealed that treatment with 0.25\u2009M sucrose before slow freezing improved the viability of bovine embryos after freeze\u2013thawing.<\/jats:p><\/jats:sec>","DOI":"10.3389\/fvets.2024.1400899","type":"journal-article","created":{"date-parts":[[2024,4,10]],"date-time":"2024-04-10T05:13:36Z","timestamp":1712726016000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":4,"title":["Slow freezing cryopreservation of Korean bovine blastocysts with an additional sucrose pre-equilibration step"],"prefix":"10.3389","volume":"11","author":[{"given":"Seungki","family":"Jung","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hyeonseok","family":"Sul","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Dongjin","family":"Oh","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yeon-Gil","family":"Jung","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Joohyeong","family":"Lee","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sang-Hwan","family":"Hyun","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2024,4,10]]},"reference":[{"key":"ref1","doi-asserted-by":"publisher","first-page":"180","DOI":"10.1016\/j.theriogenology.2020.01.024","article-title":"Follicular 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