title: Protein modification as oxidative stress marker in normal and pathological human seminal plasma.
abstract: OBJECTIVE
  Our study aims to assess the oxidative stress status of seminal plasma from normozoospermic, azoospermic, and leukocytospermic males, since abnormal sperm and leukocytes in human ejaculates are the main source of reactive oxygen species (ROS) which lead to oxidative  damages. For this purpose we applied a biochemical approach to the assessment of the oxidative stress status by using two-dimensional (2D) electrophoresis to check the level of protein oxidation after specific labeling of free thiol (-SH) groups.
  
  
  METHODS
  Seminal  plasma samples from normal and pathological males were analyzed by a luminol-based chemiluminescent assay. The same samples after specific labeling of free -SH groups with 3-N-maleimidopropionyl biocytin, were analyzed by 2D electrophoresis and computer-assisted semiquantitative  determination of the amount of free -SH groups.
  
  
  RESULTS
  Using a standard chemiluminescence assay, we demonstrated a high, low and normal level of ROS, respectively, in seminal plasma from leukocytospermic, azoospermic, and normozoospermic subjects. By 2D electrophoresis  and streptavidin blotting of specifically labeled free -SH groups of proteins, we detected in the same samples a higher level of oxidated -SH groups comparable between azoospermic and leukocytospermic samples, whereas a significantly higher level of free -SH groups was  detected in normozoospermic subjects.
  
  
  CONCLUSIONS
  Our results demonstrated that a pathological oxidative stress status in seminal plasma may be revealed by the levels of the protein free -SH groups, both in the presence or absence of cells.
authors: Department of Biomedical Sciences, Biology Section, University of Siena, Italy.
authors: Paola
authors: P
authors: Piomboni
authors: Anita
authors: A
authors: Stendardi
authors: Laura
authors: L
authors: Gambera
authors: Carla
authors: C
authors: Tatone
authors: Lamberto
authors: L
authors: Coppola
authors: Vincenzo
authors: V
authors: De Leo
authors: Riccardo
authors: R
authors: Focarelli
mesh_terms: D053713:Azoospermia / Q000378:metabolism; D015415:Biomarkers / Q000032:analysis*; D006801:Humans; D008297:Male; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000502:physiology*; D011499:Protein Processing, Post-Translational; D017382:Reactive Oxygen Species / Q000378:metabolism; D012661:Semen / Q000378:metabolism*; D013438:Sulfhydryl Compounds / Q000378:metabolism
chemical_list: D015415:Biomarkers; D017382:Reactive Oxygen Species; D013438:Sulfhydryl Compounds