title: The Defensive Role of Cumulus Cells Against Reactive Oxygen Species Insult in Metaphase II Mouse Oocytes.
abstract: We investigated the ability of reactive oxygen species (ROS), such as hydrogen peroxide (H(2)O(2)), hydroxyl radical ((·)OH), and hypochlorous acid (HOCl), to overcome the defensive capacity of cumulus cells and elucidate the mechanism through which ROS differentially deteriorate oocyte quality. Metaphase II mouse oocytes with (n = 1634) and without cumulus cells (n = 1633) were treated with increasing concentration of ROS, and the deterioration in oocyte quality was assessed by the changes in the microtubule morphology and chromosomal alignment. Oocyte and cumulus cell viability and cumulus cell number were assessed by indirect immunofluorescence, staining of gap junction protein, and trypan blue staining. The treated oocytes showed decreased quality as a function of increasing concentrations of ROS when compared to controls. Cumulus cells show protection against H(2)O(2) and (·)OH insult at lower concentrations, but this protection was lost at higher concentrations (>50 μmol/L). At higher H(2)O(2) concentrations, treatment dramatically influenced the cumulus cell number and viability with resulting reduction in the antioxidant capacity making the oocyte more susceptible to oxidative damage. However, cumulus cells offered no significant protection against HOCl at any concentration used. In all circumstances in which cumulus cells did not offer protection to the oocyte, both cumulus cell number and viability were decreased. Therefore, the deterioration in oocyte quality may be caused by one or more of the following: a decrease in the antioxidant machinery by the loss of cumulus cells, the lack of scavengers for specific ROS, and/or the ability of the ROS to overcome these defenses.
authors.affiliation: Departments of Obstetrics and Gynecology, the C.S. Mott Center for Human Growth and Development, Wayne State University School of Medicine, Detroit, MI, USA.
authors.forename: Faten
authors.initials: F
authors.lastname: Shaeib
authors.affiliation: Departments of Obstetrics and Gynecology, the C.S. Mott Center for Human Growth and Development, Wayne State University School of Medicine, Detroit, MI, USA.
authors.forename: Sana N
authors.initials: SN
authors.lastname: Khan
authors.affiliation: Departments of Obstetrics and Gynecology, the C.S. Mott Center for Human Growth and Development, Wayne State University School of Medicine, Detroit, MI, USA Department of Biochemistry and Genetics, Faculty of Medicine, An-Najah National University, Nablus, Palestine.
authors.forename: Iyad
authors.initials: I
authors.lastname: Ali
authors.affiliation: Departments of Obstetrics and Gynecology, the C.S. Mott Center for Human Growth and Development, Wayne State University School of Medicine, Detroit, MI, USA.
authors.forename: Mili
authors.initials: M
authors.lastname: Thakur
authors.affiliation: Departments of Obstetrics and Gynecology, the C.S. Mott Center for Human Growth and Development, Wayne State University School of Medicine, Detroit, MI, USA.
authors.forename: Mohammed G
authors.initials: MG
authors.lastname: Saed
authors.affiliation: Departments of Obstetrics and Gynecology, the C.S. Mott Center for Human Growth and Development, Wayne State University School of Medicine, Detroit, MI, USA.
authors.forename: Jing
authors.initials: J
authors.lastname: Dai
authors.affiliation: Departments of Obstetrics and Gynecology, the C.S. Mott Center for Human Growth and Development, Wayne State University School of Medicine, Detroit, MI, USA.
authors.forename: Awoniyi O
authors.initials: AO
authors.lastname: Awonuga
authors.affiliation: Departments of Obstetrics and Gynecology, the C.S. Mott Center for Human Growth and Development, Wayne State University School of Medicine, Detroit, MI, USA.
authors.forename: Jashoman
authors.initials: J
authors.lastname: Banerjee
authors.affiliation: Departments of Obstetrics and Gynecology, the C.S. Mott Center for Human Growth and Development, Wayne State University School of Medicine, Detroit, MI, USA Department of Biochemistry and Molecular Biology, Wayne State University School of Medicine, Detroit, MI, USA habusoud@med.wayne.edu.
authors.forename: Husam M
authors.initials: HM
authors.lastname: Abu-Soud
mesh_terms: D000818:Animals; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D054885:Cumulus Cells / Q000187:drug effects / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006861:Hydrogen Peroxide / Q000633:toxicity; D008677:Metaphase / Q000187:drug effects / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D009865:Oocytes / Q000187:drug effects / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism*
chemical_list: D017382:Reactive Oxygen Species; D006861:Hydrogen Peroxide
keywords: and inflammation; cumulus cells; hydrogen peroxide; oocyte quality; oxidative stress; reactive oxygen species