title: Systemic concentrations of antioxidants and biomarkers of macromolecular oxidative damage in horses with grass sickness.
abstract: BACKGROUND
  The aetiopathogenesis of equine grass sickness (EGS) is unknown. The role of free radical-mediated neuronal damage has not previously been investigated in this condition.
  
  
  OBJECTIVE
  To investigate the potential contribution of oxidative damage and antioxidant status to neurodegeneration in EGS.
  
  
  METHODS
  Systemic levels of surrogate biomarkers were determined in 10 horses with acute EGS and in 2 control populations; 10 healthy horses co-grazing with the 10 EGS horses at the onset of clinical disease, and 10 healthy mares grazing where EGS has not been reported.
  
  
  RESULTS
  EGS horses had alterations in levels of several antioxidants, consistent with oxidative stress, the acute phase response and/or the secondary metabolic complications of EGS. EGS horses had elevated plasma dihydroxyphenylalanine (DOPA) levels.
  
  
  CONCLUSIONS
  The elevated DOPA levels probably reflected a generalised disturbance of catecholamine metabolism rather than increased DOPA production via free radical-mediated oxidation of tyrosine. However, there was no evidence of systemic macromolecular oxidative damage.
  
  
  CONCLUSIONS
  Further work is required to determine whether macromolecular oxidative damage occurring at the neuronal level contributes to EGS.
authors.affiliation: Easter Bush Veterinary Centre, University of Edinburgh, Roslin, Midlothian EH25 9RG, UK.
authors.forename: B C
authors.initials: BC
authors.lastname: McGorum
authors.forename: R
authors.initials: R
authors.lastname: Wilson
authors.forename: R S
authors.initials: RS
authors.lastname: Pirie
authors.forename: I G
authors.initials: IG
authors.lastname: Mayhew
authors.forename: H
authors.initials: H
authors.lastname: Kaur
authors.forename: O I
authors.initials: OI
authors.lastname: Aruoma
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000032:analysis*; D001342:Autonomic Nervous System Diseases / Q000097:blood / Q000209:etiology / Q000662:veterinary*; D015415:Biomarkers / Q000097:blood; D016022:Case-Control Studies; D002851:Chromatography, High Pressure Liquid / Q000662:veterinary; D004295:Dihydroxyphenylalanine / Q000097:blood; D005227:Fatty Acids / Q000097:blood; D005260:Female; D006734:Horse Diseases / Q000097:blood* / Q000209:etiology; D006736:Horses; D018384:Oxidative Stress / Q000502:physiology*; D010939:Plant Poisoning / Q000662:veterinary; D006109:Poaceae / Q000506:poisoning; D014131:Trace Elements / Q000097:blood; D014815:Vitamins / Q000097:blood
chemical_list: D000975:Antioxidants; D015415:Biomarkers; D005227:Fatty Acids; D014131:Trace Elements; D014815:Vitamins; D004295:Dihydroxyphenylalanine