In vitro production of horse embryos predisposes to micronucleus formation, whereas time to blastocyst formation affects likelihood of pregnancy

Kaatje D Ducheyne, Marilena Rizzo, Juan Cuervo-Arango, Anthony Claes, Peter F Daels, Tom A E Stout, Marta de Ruijter-Villani

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

Invitro embryo production is an increasingly popular means of breeding horses. However, success is limited by a high incidence of early embryo loss. Although there are various possible causes of pregnancy failure, chromosomal abnormalities, including aneuploidy, are important potential contributors. This study evaluated the frequency of micronucleus formation as a proxy for aneuploidy in invitro-produced (IVP) and invivo-derived horse blastocysts. Associations between IVP embryo morphology, frequency of nuclear abnormalities and the likelihood of pregnancy were investigated. IVP blastocysts exhibited a higher frequency of cells with micronuclei than invivo-derived embryos (10% vs 1% respectively; P=0.05). This indication of chromosomal instability may explain the higher incidence of pregnancy failure after transfer of IVP embryos. However, the frequency of micronuclei was not correlated with brightfield microscopic morphological characteristics. Nevertheless, IVP embryos reaching the blastocyst stage after Day 9 of invitro culture were less likely to yield a pregnancy than embryos that developed to blastocysts before Day 9 (27% vs 69%), and embryos that had expanded before transfer were more likely to undergo embryonic death than those that had not expanded (44% vs 10%). These findings indicate that current embryo culture conditions are suboptimal and that the speed of embryo development is correlated with pregnancy survival.

Original languageEnglish
Pages (from-to)1830-1839
Number of pages10
JournalReproduction, fertility, and development
Volume31
Issue number12
DOIs
Publication statusPublished - Jan 2019
Externally publishedYes

Keywords

  • Aneuploidy
  • Animals
  • Blastocyst/cytology
  • Chromosomal Instability/physiology
  • Chromosome Aberrations/embryology
  • Embryo Loss/genetics
  • Embryo Transfer/veterinary
  • Embryo, Mammalian
  • Embryonic Development/physiology
  • Female
  • Fertilization in Vitro/methods
  • Horses/embryology
  • Male
  • Micronuclei, Chromosome-Defective/embryology
  • Pregnancy
  • Pregnancy, Animal/genetics
  • Time Factors
  • intracytoplasmic sperm injection
  • ovum pick-up
  • chromosomal instability
  • aneuploidy

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