title: Molecular mechanism of poor embryo development in postovulatory aged oocytes: mini review.
abstract: Oocyte quality is a key factor in determining embryo development; however, we have a poor understanding of what constitutes oocyte quality or the mechanisms governing it. Postovulatory aging of oocytes that have not been fertilized for a prolonged time after ovulation is known to significantly impair oocyte quality and subsequent embryo development after fertilization. Embryos derived from postovulatory-aged oocytes are prone to undergo apoptosis due to the decreased Bcl-2 expression. Postovulatory aging of oocytes changes the patterns of Ca(2+) oscillations at fertilization as a result of impaired Ca(2+) regulation in the endoplasmic reticulum. Moreover, postovulatory aging of oocytes impairs mitochondrial adenosine triphosphate production as a result of increasing oxidative stresses. Oxidative stresses also affect intracellular Ca(2+) regulation and impair embryo development after fertilization. Collectively, the mechanism of postovulatory oocyte aging might be involved in reactive oxygen species-induced mitochondrial injury followed by abnormal intracellular Ca(2+) regulation in the endoplasmic reticulum.
authors.affiliation: Department of Obstetrics and Gynecology, Yamagata University Faculty of Medicine, Yamagata, Japan.
authors.forename: Toshifumi
authors.initials: T
authors.lastname: Takahashi
authors.forename: Hideki
authors.initials: H
authors.lastname: Igarashi
authors.forename: Mitsuyoshi
authors.initials: M
authors.lastname: Amita
authors.forename: Shuichiro
authors.initials: S
authors.lastname: Hara
authors.forename: Koki
authors.initials: K
authors.lastname: Matsuo
authors.forename: Hirohisa
authors.initials: H
authors.lastname: Kurachi
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D047108:Embryonic Development; D005260:Female; D006801:Humans; D009865:Oocytes / Q000502:physiology*; D012098:Reproduction
keywords: calcium oscillation; endoplasmic reticulum; oxidative stress; postovulatory oocyte aging