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Cytoskeletal and mitochondrial properties of bovine oocytes obtained by O vum P ick‐ U p: the effects of follicle stimulation and in vitro maturation
Author(s) -
Somfai Tamás,
Matoba Satoko,
Inaba Yasushi,
Nakai Michiko,
Imai Kei,
Nagai Takashi,
Geshi Masaya
Publication year - 2015
Publication title -
animal science journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.606
H-Index - 38
eISSN - 1740-0929
pISSN - 1344-3941
DOI - 10.1111/asj.12387
Subject(s) - in vitro maturation , oocyte , biology , microbiology and biotechnology , stimulation , andrology , follicular phase , intracellular , medicine , endocrinology , embryo
Follicle stimulation by follicular stimulating hormone ( FSH ) is known to improve developmental competence of bovine oocytes obtained by O vum P ick‐ U p ( OPU ); however, the exact factors in oocytes affected by this treatment have remained unclear. We compared in vitro matured ( IVM ) oocytes obtained at the immature stage from cows by OPU either without or with stimulation with FSH (non‐stimulated and stimulated OPU , respectively) to those obtained by superstimulation and in vivo maturation in terms of cytoskeleton morphology, mitochondrial distribution, intracellular adenosine triphosphate ( ATP ) content and H 2 O 2 levels at the metaphase‐ II stage and intracellular Ca 2+ levels after in vitro fertilization ( IVF ). Confocal microscopy after immunostaining revealed reduced size of the meiotic spindle, associated with increased tendencies of microfilament degradation and insufficient mitochondrial re‐distribution in non‐stimulated OPU ‐derived IVM oocytes compared with those collected by stimulated OPU , which in turn resembled in vivo matured oocytes. However, there was no difference in mitochondrial functions between oocytes obtained by stimulated or non‐stimulated OPU in terms of ATP content, cytoplasmic H 2 O 2 levels, base Ca 2+ levels and the frequencies and amplitudes of Ca 2+ oscillations after IVF . Larger size of metaphase spindles in oocytes obtained by stimulated OPU may reflect and potentially contribute to their high developmental competence.