Removal of cumulus cells around 20 h after the start of <i>in vitro</i> maturation improves the meiotic competence of porcine oocytes via reduction in cAMP and cGMP levels

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Author(s)

    • NGUYEN Xuan Khanh NGUYEN Xuan Khanh
    • Department of Animal Science, Graduate School of Environmental and Life Science, Okayama University, Okayama 700-8530, Japan|Department of Veterinary and Animal Science, Nong Lam University, Ho Chi Minh City, Vietnam
    • BUI Thi Tra Mi BUI Thi Tra Mi
    • Department of Animal Science, Graduate School of Environmental and Life Science, Okayama University, Okayama 700-8530, Japan|Department of Veterinary and Animal Science, Nong Lam University, Ho Chi Minh City, Vietnam
    • WAKAI Takuya WAKAI Takuya
    • Department of Animal Science, Graduate School of Environmental and Life Science, Okayama University, Okayama 700-8530, Japan

Abstract

<p> We examined the effect of the timing of removing cumulus cells surrounding porcine oocytes from small follicles (SFs, < 3 mm in diameter) and medium follicles (MFs; 3–6 mm in diameter) on the meiotic and developmental competence of the oocytes. Cumulus-oocyte complexes (COCs) were collected from SFs and MFs, and the oocytes were denuded at 0, 20, and 44 h after the start of <i>in vitro</i> maturation (IVM), and the meiotic progression of the oocytes was assessed at the end of the IVM period. The incidence of mature oocytes was significantly affected by both the origin of the COCs and the time when the oocytes were denuded. Although the percentage of mature oocytes was always higher when the COCs were collected from MFs than that when the COCs were collected from SFs, the maturation rate was significantly higher when the oocytes were denuded at 20 h than when they were denuded at 44 h after the start of IVM. When the mature oocytes were activated electrically, the developmental competence of the oocytes denuded at 20 and 44 h to reach the blastocyst stage did not differ, whereas the competence of the MF-derived oocytes was significantly higher than that of SF-derived oocytes. When the intracellular cAMP and cGMP levels in SF-derived oocytes were examined at 24 h of IVM, the levels of both were significantly decreased only in the oocytes denuded at 20 h. In conclusion, denuding oocytes at 20 h of IVM caused a significant reduction in ooplasmic cAMP and cGMP levels and increased the meiotic competence of the oocytes without any reduction in blastocyst formation, even in the case of SF-derived oocytes.</p>

Journal

  • Journal of Reproduction and Development

    Journal of Reproduction and Development 65(2), 177-182, 2019

    THE SOCIETY FOR REPRODUCTION AND DEVELOPMENT

Codes

  • NII Article ID (NAID)
    130007630932
  • NII NACSIS-CAT ID (NCID)
    AA10936678
  • Text Lang
    ENG
  • ISSN
    0916-8818
  • NDL Article ID
    029637698
  • NDL Call No.
    Z54-H305
  • Data Source
    NDL  J-STAGE 
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