title: Human sperm chemotaxis depends on critical levels of reactive oxygen species.
abstract: OBJECTIVE
  To verify whether chemotaxis is in part an oxidative process mediated by reactive oxygen species (ROS).
  
  
  METHODS
  In this prospective study, after removal of seminal plasma, the sperm suspension received no treatment (control), ROS formation by stimulation with phorbol 12-myristate 13-acetate (PMA), antioxidant treatment (with catalase), or PMA stimulus in the presence of catalase. At time zero and after 3 hours of incubation, the percentage of capacitated and oriented spermatozoa and the ROS levels were determined.
  
  
  METHODS
  Andrology laboratory in a medical research institution.
  
  
  METHODS
  Normal semen was obtained from eight men.
  
  
  METHODS
  The semen samples were evaluated to determine the effect of ROS production by stimulation with PMA and/or antioxidant treatment (with catalase) on the percentage of capacitated and oriented spermatozoa.
  
  
  METHODS
  The sperm capacitation, chemotaxis and reactive oxygen species were assessed before and after PMA and/or antioxidant treatment.
  
  
  RESULTS
  Prolonged exposure to high quantities of ROS decrease the sperm chemotactic response, probably because of oxidative damage of the cell. However, this effect may be reduced by the addition of antioxidants like catalase.
  
  
  CONCLUSIONS
  Similar to capacitation, chemotaxis seems to depend on the production of ROS, but in the latter process there may be a critical level of ROS necessary for chemotaxis to occur.
authors.affiliation: Center of Reproductive Biotechnology, Faculty of Medicine, Universidad de La Frontera, Temuco, Chile. rsanchez@ufro.cl
authors.forename: Raúl
authors.initials: R
authors.lastname: Sánchez
authors.forename: Carolina
authors.initials: C
authors.lastname: Sepúlveda
authors.forename: Jennie
authors.initials: J
authors.lastname: Risopatrón
authors.forename: Juana
authors.initials: J
authors.lastname: Villegas
authors.forename: Laura C
authors.initials: LC
authors.lastname: Giojalas
mesh_terms: D000975:Antioxidants / Q000378:metabolism; D002374:Catalase / Q000378:metabolism; D002633:Chemotaxis / Q000187:drug effects; D006801:Humans; D008297:Male; D016877:Oxidants / Q000494:pharmacology; D018384:Oxidative Stress / Q000187:drug effects; D011446:Prospective Studies; D017382:Reactive Oxygen Species / Q000378:metabolism*; D013075:Sperm Capacitation; D013094:Spermatozoa / Q000187:drug effects / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D013997:Time Factors
chemical_list: D000975:Antioxidants; D016877:Oxidants; D017382:Reactive Oxygen Species; D002374:Catalase; D013755:Tetradecanoylphorbol Acetate