Invitro 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
    JournalReproduction, Fertility and Development
    Volume31
    Issue number12
    Early online date27 Nov 2019
    DOIs
    Publication statusPublished - 27 Nov 2019

    Keywords

    • aneuploidy
    • chromosomal instability
    • intracytoplasmic sperm injection
    • ovum pick-up

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