title: Low amounts and high thiol oxidation of peroxiredoxins in spermatozoa from infertile men.
abstract: Seminal oxidative stress occurs when there is an increased production of  reactive oxygen species (ROS) and/or a decrease of antioxidant activity,  promoting impaired sperm function. Peroxiredoxins (PRDX) are abundant in human  semen and are important antioxidant enzymes, which act as ROS scavengers and  modulators in ROS-dependent signaling. Our aim was to determine whether the  levels of PRDX1 and PRDX6 and their oxidation on thiol groups are associated  with a decrease in sperm motility and DNA integrity. We evaluated the sperm  and seminal PRDX level in men (13 healthy controls, 15 men with clinical  varicocele, and 17 men with idiopathic infertility). We assessed conventional  semen parameters, sperm DNA integrity (by the sperm chromatin structure  assay), lipid peroxidation in seminal plasma and spermatozoa (by the  thiobarbituric acid reactive substances assay), and the amount and thiol  oxidation of PRDX1 and PRDX6 (by immunoblotting). PRDXs were affected in  seminal plasma (lower amounts) and in sperm samples (lower amounts and higher  levels of thiol oxidation) characterized by lower sperm motility, higher lipid  peroxidation, and sperm DNA damage. The thioloxidation ratio of PRDXs  (thiol-oxidized PRDX/total PRDX) correlated negatively with sperm motility  (total and progressive) and positively with sperm DNA damage and sperm lipid  peroxidation. In conclusion, because of the lower amount of total PRDX1 and  PRDX6 and the high thiol oxidation of these PRDXs, very little (less than 20%)  protection due to PRDXs remains, and this is associated with impaired sperm  function and poor DNA integrity and suggests an important role of PRDXs in the  protection of human spermatozoa against oxidative stress.
authors.affiliation: Urology Research Laboratory, Research Institute of the McGill University Health Centre, McGill University, Montréal, Québec, Canada.
authors.forename: Shasha
authors.initials: S
authors.lastname: Gong
authors.forename: Maria C
authors.initials: MC
authors.lastname: San Gabriel
authors.forename: Armand
authors.initials: A
authors.lastname: Zini
authors.forename: Peter
authors.initials: P
authors.lastname: Chan
authors.forename: Cristian
authors.initials: C
authors.lastname: O'Flaherty
mesh_terms: D004249:DNA Damage; D006801:Humans; D007248:Infertility, Male / Q000503:physiopathology*; D015227:Lipid Peroxidation; D008297:Male; D018384:Oxidative Stress; D054465:Peroxiredoxin VI / Q000378:metabolism*; D054464:Peroxiredoxins / Q000378:metabolism*; D012661:Semen / Q000378:metabolism; D013094:Spermatozoa / Q000378:metabolism*; D013438:Sulfhydryl Compounds / Q000378:metabolism; D014646:Varicocele / Q000503:physiopathology
chemical_list: D013438:Sulfhydryl Compounds; C515940:PRDX1 protein, human; C515977:PRDX6 protein, human; D054465:Peroxiredoxin VI; D054464:Peroxiredoxins