title: Nitric oxide modulates mitochondrial activity and apoptosis through protein S-nitrosylation for preimplantation embryo development.
abstract: OBJECTIVE
  Previous studies reported that patients with endometriosis had excess nitric oxide (NO) in the reproductive tract and poor embryo development in IVF cycles. This study aims to elucidate the effects of NO on early embryo development.
  
  
  METHODS
  Zygotes from superovulated B6CBF1 mice were cultured to blastocysts in a variety of media. Sodium nitroprusside (SNP) and N(G)-nitro-L-arginine (LNA) were added to the culture medium as a NO donor and a NO synthase inhibitor, respectively. The localization and fluorescence intensity of S-nitrosylated (SNO) proteins within 2-cell stage embryos were analyzed with confocal microscopy. Apoptosis and ATP production in the blastocysts were measured.
  
  
  RESULTS
  Subsequent to NO exposure, the SNO proteins mainly colocalized with the mitochondria and endoplasmic reticulum and the intensity of SNO proteins increased. The addition of a quanylate cyclase inhibitor and a cyclic GMP mimic agent induced nonsignificant changes in SNO proteins, whereas addition of a superoxide scavenger or a reduced form of glutathione rescued the embryos from the effects of NO. However, superoxide scavenger supplementation resulted in decreased blastocyst ATP production.
  
  
  CONCLUSIONS
  Elevated NO exerts deleterious effects on embryo development, possibly through protein S-nitrosylation in the mitochondria and endoplasmic reticulum. Including glutathione as a component in the culture medium might counteract this effect.
authors.affiliation: Department of Obstetrics and Gynecology, National Taiwan University and National Taiwan University Hospital, #8 Chung-Shan South Road, 100, Taipei, Taiwan.
authors.forename: Tsung-Hsien
authors.initials: TH
authors.lastname: Lee
authors.forename: Maw-Sheng
authors.initials: MS
authors.lastname: Lee
authors.forename: Chun-Chia
authors.initials: CC
authors.lastname: Huang
authors.forename: Hui-Mei
authors.initials: HM
authors.lastname: Tsao
authors.forename: Pi-Mei
authors.initials: PM
authors.lastname: Lin
authors.forename: Hong-Nerng
authors.initials: HN
authors.lastname: Ho
authors.forename: Jin-Yuh
authors.initials: JY
authors.lastname: Shew
authors.forename: Yu-Shih
authors.initials: YS
authors.lastname: Yang
mesh_terms: D000818:Animals; D017209:Apoptosis; D001755:Blastocyst / Q000166:cytology / Q000187:drug effects* / Q000648:ultrastructure; D046149:Embryo Culture Techniques; D047108:Embryonic Development / Q000187:drug effects*; D051379:Mice; D008928:Mitochondria / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D009569:Nitric Oxide / Q000633:toxicity*
chemical_list: D009569:Nitric Oxide