Efficient Strontium-Induced Activation of Mouse Oocytes in Standard Culture Media by Chelating Calcium

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Author(s)

Abstract

Without using sperm, artificial oocyte activation is essential for current assisted reproductive technologies, particularly somatic cell nuclear transfer and round spermatid injection. Strontium has been widely used as an activator of oocytes especially in the mouse, by which efficient oocyte activation requires Ca<sup>2+</sup>-free medium. In this study, we examined whether Sr<sup>2+</sup> can efficiently activate oocytes in Ca<sup>2+</sup>-containing culture media when calcium is chelated. Ethylene glycol-bis (β-aminoethyl ether) -N, N, N', N'-tetraacetic acid (EGTA) was added to three standard culture media (CZB, M16 and KSOM) for mouse embryos because it preferentially binds Ca<sup>2+</sup> rather than Sr<sup>2+</sup>. We found that treatment with 5 mM Sr<sup>2+</sup> and 2 mM EGTA left fewer than 1% of oocytes at the MII stage, which is comparable to that of Ca<sup>2+</sup>-free medium. As a result, addition of 2 mM EGTA along with 5 mM Sr<sup>2+</sup> in either CZB, M16 or KSOM made more than 80% of available activated oocytes, which was comparable to or better than 72% in a Ca<sup>2+</sup>-free Sr<sup>2+</sup> medium, since EGTA-Sr<sup>2+</sup> activation led to significantly less oocyte degeneration than Ca<sup>2+</sup>-free Sr<sup>2+</sup> activation. Furthermore, we demonstrated that this activation method can support the birth of cloned embryos. Thus, addition of EGTA to typical Ca<sup>2+</sup>-containing culture media can easily produce activation media that does not interfere with embryonic development.<br>

Journal

  • Journal of Reproduction and Development

    Journal of Reproduction and Development 53(6), 1207-1215, 2007-12-01

    THE SOCIETY FOR REPRODUCTION AND DEVELOPMENT

References:  34

Cited by:  4

Codes

  • NII Article ID (NAID)
    10020172730
  • NII NACSIS-CAT ID (NCID)
    AA10936678
  • Text Lang
    ENG
  • Article Type
    Journal Article
  • ISSN
    09168818
  • NDL Article ID
    9327021
  • NDL Source Classification
    ZR22(科学技術--農林水産--畜産)
  • NDL Call No.
    Z54-H305
  • Data Source
    CJP  CJPref  NDL  J-STAGE 
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