The vitrification of immature germinal vesicle (GV) oocytes is an important way to preserve genetic resources and female fertility. However, it is well known that cryopreserved GV oocytes have very poor developmental ability and that further improvement in this technique is needed. We previously reported the successful vitrification of matured mouse oocytes with enclosed cumulus cells using the calcium-free vitrification solution supplemented with ethylene glycol (EG) by the minimal volume cooling (MVC) method. In this study, we investigated whether our method is applicable to the vitrification of mouse oocytes at the GV stage (GV oocytes). Following maturation and fertilization in vitro, vitrified GV oocytes showed high survival (94.3 ± 2.0%) and maturation (94.3 ± 2.1%) rates. Although the fertilization and blastocyst rates of vitrified oocytes (fertilization: 46.6 ± 4.9% and blastocyst: 46.6 ± 3.0%) were significantly lower than those of fresh oocytes (fertilization: 73.0 ± 7.1% and blastocyst: 71.6 ± 8.0%) (P < 0.01), there were no differences in the ability to develop to term between fresh oocytes (50.0 ± 8.4%) and vitrified oocytes (37.5 ± 4.6%) (P > 0.05). In conclusion, we here show, for the first time, the efficient production of live mice derived from vitrified GV oocytes.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7951897 | PMC |
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0248050 | PLOS |
Hum Reprod
January 2025
IVIRMA Global Research Alliance, IVIRMA New Jersey, Basking Ridge, NJ, USA.
Study Question: Does the use of slush nitrogen (SN) for embryo vitrification improve embryo transfer outcomes compared to liquid nitrogen (LN)?
Summary Answer: SN is a safe method for embryo preservation and significantly improves post-warming survival rates during repeated vitrification-warming cycles; however, after a single freeze-thaw cycle, pregnancy outcomes are not improved when embryos are vitrified with SN compared to LN.
What Is Known Already: SN is a combination of solid and LN, with a temperature lower than regular LN, and it is an alternative to conventional LN in achieving a faster cooling speed. Studies have shown that SN improves survival in non-human embryos and human oocytes.
Aim: Within the in vitro fertilization (IVF) process, to evaluate the possibility of using the state of the meiotic spindle of oocytes as an indicator of maturity in order to optimize the timing of vitrification.
Patients And Methods: In the presented report, the cause of couple infertility was a combination of a 38-year-old female and 43-year-old male with azoospermia, which was an indication for oocyte vitrification. Oocyte polar bodies and optically birefringent meiotic spindles were visualized by polarized light microscopy and their states and relative positions were used as indicators of oocyte maturation, i.
J Equine Vet Sci
January 2025
Veterinary Reproduction Group, Faculty of Veterinary Medicine, University of Cordoba, Spain. Electronic address:
Sperm vitrification is an alternative freezing method, which includes high cooling rates and non-permeable cryoprotectants agents. The first attempt in equids was using the spheres technique by directly dropping small volumes of the sperm into liquid nitrogen. Later, vitrification was developed using 0.
View Article and Find Full Text PDFJ Assist Reprod Genet
January 2025
Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA.
Purpose: This study is to evaluate duration of oocyte cryostorage and association with thaw survival, fertilization, blastulation, ploidy rates, and pregnancy outcomes in patients seeking fertility preservation.
Methods: Retrospective cohort study to evaluate clinical outcomes in patients who underwent fertility preservation from 2011 to 2023 via oocyte vitrification for non-oncologic indications. Primary outcome was thaw survival rate.
J Assist Reprod Genet
December 2024
Departament of Reproductive Medicine, Instituto Bernabeu, Alicante, Spain.
Purpose: To compare the efficacy of modified natural cycle (mNC) preparation versus hormone replacement therapy (HRT) for endometrial preparation in recipients of donated oocytes, specifically focusing on pregnancy rates in women of advanced maternal age.
Methods: Retrospective multicenter analysis conducted between 2021 and 2024. It includes 220 cycles of fresh single blastocyst transfers resulting from oocyte donation.
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