Assessment of Meiotic Spindle Configuration and Post-Warming Bovine Oocyte Viability Using Polarized Light Microscopy

Authors

  • JN Caamaño,

    Corresponding author
    • Genética y Reproducción Animal, Centro de Biotecnología Animal, Servicio Regional de Investigación y Desarrollo Agroalimentario, Gijón, Principado de Asturias, Spain
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  • C Díez,

    1. Genética y Reproducción Animal, Centro de Biotecnología Animal, Servicio Regional de Investigación y Desarrollo Agroalimentario, Gijón, Principado de Asturias, Spain
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  • B Trigal,

    1. Genética y Reproducción Animal, Centro de Biotecnología Animal, Servicio Regional de Investigación y Desarrollo Agroalimentario, Gijón, Principado de Asturias, Spain
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  • M Muñoz,

    1. Genética y Reproducción Animal, Centro de Biotecnología Animal, Servicio Regional de Investigación y Desarrollo Agroalimentario, Gijón, Principado de Asturias, Spain
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  • R Morató,

    1. Departament de Medicina i Cirurgia Animals, Universitat Autònoma de Barcelona, Bellaterra, Spain
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  • D Martín,

    1. Genética y Reproducción Animal, Centro de Biotecnología Animal, Servicio Regional de Investigación y Desarrollo Agroalimentario, Gijón, Principado de Asturias, Spain
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  • S Carrocera,

    1. Genética y Reproducción Animal, Centro de Biotecnología Animal, Servicio Regional de Investigación y Desarrollo Agroalimentario, Gijón, Principado de Asturias, Spain
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  • T Mogas,

    1. Departament de Medicina i Cirurgia Animals, Universitat Autònoma de Barcelona, Bellaterra, Spain
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  • E Gómez

    1. Genética y Reproducción Animal, Centro de Biotecnología Animal, Servicio Regional de Investigación y Desarrollo Agroalimentario, Gijón, Principado de Asturias, Spain
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Author's address (for correspondence): JN Caamaño, Area de Genética y Reproducción, Centro de Biotecnología Animal, SERIDA, Camino de Rioseco 1225, La Olla, Deva, 33394 Gijón, Principado de Asturias, Spain. E-mail: jncaamano@serida.org

Contents

The objectives of this study were to assess the efficiency of polarized light microscopy (PLM) in detecting microtubule-polymerized protein in in vitro-matured bovine oocytes; to examine its effects on oocyte developmental competence; and to assess the meiotic spindle of in vitro-matured oocytes after vitrification/warming and further assessment of oocyte developmental competence. In the first experiment, the presence of microtubule-polymerized protein (MPP) was confirmed as a positive PLM signal detected in 99.1% of analysed oocytes (n = 115), which strongly correlated (r = 1; p < 0.0001) with the presence of MPP as confirmed by immunostaining. In the second experiment, oocytes (n = 651) were exposed or not (controls) to PLM for 10 min and then fertilized and cultured in vitro. Oocytes exposed to PLM did not significantly differ from controls with regard to cleavage, total blastocyst and expanded blastocyst rates and cell numbers. In the third experiment, meiotic spindles were detected in 145 of 182 oocytes (79.6%) following vitrification and warming. Interestingly, after parthenogenetic activation and in vitro culture, oocytes that displayed a positive PLM signal PLM(+) differed significantly from PLM(−) in cleavage and Day 8 blastocyst rates. These results suggest that polarized light microscopy is an efficient system to detect microtubule-polymerized protein in in vitro-matured bovine oocytes and does not exert detrimental effects on bovine oocyte developmental competence. Moreover, PLM could be used as a tool to assess post-warming viability in vitrified bovine oocytes.

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