title: Caspase 3 activation in human spermatozoa in response to hydrogen peroxide and progesterone.
abstract: OBJECTIVE
  To determine the role of calcium signaling on apoptosis evoked by the reactive oxygen species H2O2 and by the physiological agonist P in human ejaculated spermatozoa.
  
  
  METHODS
  Laboratory study.
  
  
  METHODS
  Center for assisted human reproduction in a hospital in Spain.
  
  
  METHODS
  Forty-five healthy volunteers.
  
  
  METHODS
  Spermatozoa were treated with increasing concentrations of hydrogen peroxide (H2O2; 10 microM, 100 microM, and 1 mM) or with 20 microM of P for 5-120 minutes.
  
  
  METHODS
  Activation of caspase-3 and -9 as well as phosphatidylserine externalization were examined in human ejaculated spermatozoa by fluorescence methods.
  
  
  RESULTS
  Hydrogen peroxide and P induced activation of caspase-3 and -9. In addition, the effect of H2O2 and P was time dependent. Dimethyl-1,2-bis (aminophenoxy) ethane-N,N,N',N'-tetraacetic acid loading was able to inhibit H2O2- and P-induced caspase-3 activation and phosphatidylserine externalization. Pretreatment of spermatozoa with Ru360, to block the calcium uptake into mitochondria, also was able to decrease the activation of caspase-3 and phosphatidylserine exposure that was stimulated by either H2O2 or P.
  
  
  CONCLUSIONS
  These findings suggest that H2O2- and P-induced mitochondrial apoptosis is dependent on calcium signaling.
authors.affiliation: Department of Physiology, Faculty of Science, University of Extremadura, Badajoz, Spain.
authors.forename: Ignacio
authors.initials: I
authors.lastname: Bejarano
authors.forename: Graciela M
authors.initials: GM
authors.lastname: Lozano
authors.forename: Agueda
authors.initials: A
authors.lastname: Ortiz
authors.forename: Juan F
authors.initials: JF
authors.lastname: García
authors.forename: Sergio D
authors.initials: SD
authors.lastname: Paredes
authors.forename: Ana B
authors.initials: AB
authors.lastname: Rodríguez
authors.forename: José A
authors.initials: JA
authors.lastname: Pariente
mesh_terms: D017209:Apoptosis; D002118:Calcium / Q000378:metabolism; D020013:Calcium Signaling; D053148:Caspase 3 / Q000378:metabolism*; D053453:Caspase 9 / Q000378:metabolism; D004789:Enzyme Activation; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism*; D008297:Male; D011374:Progesterone / Q000378:metabolism*; D013094:Spermatozoa / Q000166:cytology / Q000201:enzymology*
chemical_list: D011374:Progesterone; D006861:Hydrogen Peroxide; D053148:Caspase 3; D053453:Caspase 9; D002118:Calcium