Cryopreservation of equine oocytes: Looking into the crystal ball

Tine De Coster*, Daniel Angel Velez, Ann Van Soom, Henri Woelders, Katrien Smits

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

In vitro embryo production has evolved rapidly in the horse over the past decade, but blastocyst rates from vitrified equine oocytes remain quite poor and further research is needed to warrant application. Oocyte vitrification is affected by several technical and biological factors. In the horse, short exposure of immature oocytes to the combination of permeating and non-permeating cryoprotective agents has been associated with the best results so far. High cooling and warming rates are also crucial and can be obtained by using minimal volumes and open cryodevices. Vitrification of in vivo-matured oocytes has yielded better results, but is less practical. The presence of the corona radiata seems to partially protect those factors that are necessary for the construction of the normal spindle and for chromosome alignment, but multiple layers of cumulus cells may impair permeation of cryoprotective agents. In addition to the spindle, the oolemma and mitochondria are also particularly sensitive to vitrification damage, which should be minimised in future vitrification procedures. This review presents promising protocols and novel strategies in equine oocyte vitrification, with a focus on blastocyst development and foal production as most reliable outcome parameters.

Original languageEnglish
Pages (from-to)453-467
Number of pages15
JournalReproduction, Fertility and Development
Volume32
Issue number5
DOIs
Publication statusPublished - 1 Mar 2020

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Keywords

  • blastocyst
  • cumulus cells
  • intracytoplasmic sperm injection
  • maturation
  • vitrification

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