title: Arsenite induces aberrations in meiosis that can be prevented by coadministration of N-acetylcysteine in mice.
abstract: OBJECTIVE
  To evaluate in vitro effects of arsenite and of arsenite plus N-acetylcysteine on mouse oocyte meiosis.
  
  
  METHODS
  Morphological study using mouse oocytes submitted to in vitro maturation (IVM).
  
  
  METHODS
  Laboratory of reproductive biology.
  
  
  METHODS
  Six-week-old CD-1 mice superovulated with pregnant mare serum gonadotropin.
  
  
  METHODS
  During IVM, mouse oocytes were exposed to arsenite alone or to arsenite plus N-acetylcysteine.
  
  
  METHODS
  Meiotic anomalies were assessed using immunofluorescence microscopy and PolScope (Cambridge Research and Instrumentation, Boston, MA) imaging.
  
  
  RESULTS
  In vitro arsenite administration produced dose-dependent and time-dependent meiotic anomalies, characterized by spindle disruption or chromosome misalignment. After 12-14 hours of IVM, exposure to 2 microg/mL of arsenite for 12-14 hours or to 8 microg/mL of arsenite for 2 hours arrested oocyte maturation at the germinal vesicle or germinal-vesicle breakdown stage. Exposure to 4 microg/mL of arsenite for 2 hours arrested oocyte maturation at metaphase I stage in 95% of exposed oocytes (80% exhibiting abnormalities) after 12-14 hours in IVM. After 12-14 hours in IVM, of the oocytes exposed to 2 microg/mL of arsenite for 2 hours, only 15% reached the meiosis II stage (5% exhibiting abnormalities). After 15-17 hours in IVM, however, of the oocytes exposed to 2 microg/mL of arsenite for 2 hours, 65.2% reached the meiosis II stage (43.5% exhibiting abnormalities). Co-administration of N-acetylcysteine prevented the arsenite-induced meiotic abnormalities and the delayed IVM.
  
  
  CONCLUSIONS
  In vitro arsenite exposure caused meiotic abnormalities that were prevented by co-administration of N-acetylcysteine, suggesting that arsenite-induced meiotic aberrations are mediated by reactive oxygen species.
authors.affiliation: Department of Obstetrics and Gynecology, Women and Infants Hospital, Brown University, Providence, Rhode Island, USA. paasnavarro@uol.com.br
authors.forename: Paula A A S
authors.initials: PA
authors.lastname: Navarro
authors.forename: Lin
authors.initials: L
authors.lastname: Liu
authors.forename: Rui A
authors.initials: RA
authors.lastname: Ferriani
authors.forename: David L
authors.initials: DL
authors.lastname: Keefe
mesh_terms: D000111:Acetylcysteine / Q000008:administration & dosage*; D000818:Animals; D018053:Arsenites / Q000633:toxicity*; D002478:Cells, Cultured; D002869:Chromosome Aberrations / Q000139:chemically induced*; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D004785:Environmental Pollutants / Q000633:toxicity*; D008540:Meiosis / Q000187:drug effects*; D051379:Mice; D009865:Oocytes / Q000187:drug effects* / Q000473:pathology*
chemical_list: D018053:Arsenites; D004785:Environmental Pollutants; C015001:arsenite; D000111:Acetylcysteine