title: Oxidative DNA damage impairs global sperm DNA methylation in infertile men.
abstract: OBJECTIVE
  Methylation of sperm DNA is impaired in many infertile men potentially adversely effecting reproductive outcomes. In somatic cells oxidative damage to DNA and hyperhomocysteinaemia are linked with DNA hypomethylation. The objective of this study was to investigate if these pathologies also impair sperm DNA methylation.
  
  
  METHODS
  The relationship between sperm DNA quality, oxidative stress and serum homocysteine was analysed at study entry and after 3 months of antioxidant treatment.
  
  
  RESULTS
  Overall a significant negative correlation was observed between sperm DNA methylation and sperm DNA fragmentation, as well as seminal reactive oxygen species (ROS) production. Sperm DNA methylation was not significantly related to serum homocysteine concentrations. Administration of an antioxidant supplement produced a significant fall in seminal ROS levels and sperm DNA fragmentation, while increasing sperm DNA methylation.
  
  
  CONCLUSIONS
  These results suggest that oxidative stress related damage to sperm DNA impedes the process of methylation, while antioxidant supplementation appears to have the potential to reduce DNA damage and normalize sperm DNA methylation.
authors.affiliation: Research Centre for Reproductive Health, Discipline of Obstetrics and Gynaecology, School of Paediatrics and Reproductive Health, University of Adelaide, Adelaide, South Australia.
authors.forename: Ozlem
authors.initials: O
authors.lastname: Tunc
authors.forename: Kelton
authors.initials: K
authors.lastname: Tremellen
mesh_terms: D000975:Antioxidants / Q000627:therapeutic use; D004249:DNA Damage; D053938:DNA Fragmentation; D019175:DNA Methylation / Q000502:physiology*; D006710:Homocysteine / Q000097:blood; D006801:Humans; D007248:Infertility, Male / Q000378:metabolism / Q000473:pathology*; D008297:Male; D018384:Oxidative Stress; D017382:Reactive Oxygen Species / Q000378:metabolism; D013081:Sperm Motility; D013094:Spermatozoa / Q000378:metabolism / Q000473:pathology; D016896:Treatment Outcome
chemical_list: D000975:Antioxidants; D017382:Reactive Oxygen Species; D006710:Homocysteine