Microdroplet <i>In Vitro</i> Fertilization Can Reduce the Number of Spermatozoa Necessary for Fertilizing Oocytes

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Author(s)

    • INOUE Kimiko
    • RIKEN BioResource Center, Tsukuba, Ibaraki 305-0074, Japan|Graduate School of Life and Environmental Science, University of Tsukuba, Ibaraki 305-8572, Japan
    • OGURA Atsuo
    • RIKEN BioResource Center, Tsukuba, Ibaraki 305-0074, Japan|Graduate School of Life and Environmental Science, University of Tsukuba, Ibaraki 305-8572, Japan|The Center for Disease Biology and Integrative Medicine, Faculty of Medicine, University of Tokyo, Tokyo 113-0033, Japan

Abstract

Successful <i>in vitro</i> fertilization (IVF) in mice has been achieved using spermatozoa at concentrations specifically optimized for the experimental conditions, such as species and source of spermatozoa. Although IVF in mice is mostly performed using about 80–500 µl drops, it is expected that the number of spermatozoa used for insemination can be reduced by decreasing the size of the IVF drops. The present study was undertaken to examine the extent to which the number of spermatozoa used for IVF could be reduced by using small droplets (1 µl). We devised the experimental parameters using frozen–thawed spermatozoa from C57BL/6 mice in anticipation of broader applications to other mouse facilities. We found that as few as 5 spermatozoa per droplet could fertilize oocytes (1 or 3 oocytes per droplet), although the fertilization rates were low (13–15%). Practical fertilization rates (> 40%) could be achieved with frozen-thawed C57BL/6J spermatozoa, which are sensitive to cryopreservation, when 20 sperm per droplet were used to inseminate 3 oocytes. Even with spermatozoa from a very poor quality suspension (10% motility), about 25% of oocytes were fertilized. Our calculations indicate that the number of inseminated spermatozoa per oocyte can be reduced to 1/96–1/240 by this method. In two separate embryo transfer experiments, 60% and 47%, respectively, of embryos developed to term. Our microdroplet IVF method may be particularly advantageous when only a limited number of motile spermatozoa are available because of inadequate freezing-thawing or genetic reasons.

Journal

  • Journal of Reproduction and Development

    Journal of Reproduction and Development 60(3), 187-193, 2014

    THE SOCIETY FOR REPRODUCTION AND DEVELOPMENT

Codes

  • NII Article ID (NAID)
    130003390827
  • NII NACSIS-CAT ID (NCID)
    AA10936678
  • Text Lang
    ENG
  • ISSN
    0916-8818
  • NDL Article ID
    025538109
  • NDL Call No.
    Z54-H305
  • Data Source
    NDL  J-STAGE 
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