title: Influence of repeated arthrocentesis and exercise on synovial fluid concentrations of nitric oxide, prostaglandin E2 and glycosaminoglycans in healthy equine joints.
abstract: BACKGROUND
  The importance of osteoarthritis (OA) in the horse and the difficulty in its early diagnosis have led to a search for potential biomarkers of joint disease. If the levels of such markers are to be interpreted accurately, clinicians and researchers need to know whether they are influenced by environmental factors and/or interventions such as exercise and repeated arthrocentesis.
  
  
  OBJECTIVE
  To investigate the influence of repeated arthrocentesis and exercise on nitric oxide (NO), prostaglandin E2 (PGE2) and glycosaminoglycan (GAG) concentrations in synovial fluid (SF) from normal equine joints.
  
  
  METHODS
  SF was collected from the left metacarpophalangeal (MCP), radiocarpal and tarsocrural joints of 16 horses. Half of the horses were exercised and arthrocentesis was repeated 14, 14.5, 17 and 24 days after the start of the exercise programme, in both exercised and control horses. Nitric oxide was determined in SF from the MCP joint only and PGE2 and GAG concentrations were determined in SF from all joints.
  
  
  RESULTS
  Repeated arthrocentesis caused an increase in NO concentration in the MCP joint on Day 145, in PGE2 concentrations in the radiocarpal and tarsocrural joints on Day 145 and the release of GAGs into SF of the MCP and radiocarpal joints on Day 17. Exercise resulted in an increase in PGE2 levels in all joints but did not influence the other parameters measured.
  
  
  CONCLUSIONS
  Repeated arthrocentesis is a potential confounding factor for the use of synovial NO, PGE2 and GAG concentrations as markers of joint disease. Based on this study, such a confounding effect can be avoided if one week or more separates arthrocentesis procedures. Moderate exercise causes a transient rise in PGE2 in SF.
authors.affiliation: Departments of Equine Sciences, Faculty of Veterinary Medicine, University of Utrecht, Yalelaan 12, 3584 CM, Utrecht, The Netherlands.
authors.forename: R
authors.initials: R
authors.lastname: van den Boom
authors.forename: C H A
authors.initials: CH
authors.lastname: van de Lest
authors.forename: S
authors.initials: S
authors.lastname: Bull
authors.forename: R A J
authors.initials: RA
authors.lastname: Brama
authors.forename: P R
authors.initials: PR
authors.lastname: van Weeren
authors.forename: A
authors.initials: A
authors.lastname: Barneveld
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000032:analysis; D015232:Dinoprostone / Q000032:analysis*; D005260:Female; D006025:Glycosaminoglycans / Q000032:analysis*; D006734:Horse Diseases / Q000175:diagnosis; D006736:Horses / Q000378:metabolism*; D007592:Joint Diseases / Q000175:diagnosis / Q000662:veterinary; D007596:Joints / Q000737:chemistry; D008297:Male; D009569:Nitric Oxide / Q000032:analysis*; D019152:Paracentesis / Q000009:adverse effects / Q000379:methods / Q000662:veterinary; D010805:Physical Conditioning, Animal / Q000009:adverse effects; D013582:Synovial Fluid / Q000737:chemistry*; D013997:Time Factors
chemical_list: D015415:Biomarkers; D006025:Glycosaminoglycans; D009569:Nitric Oxide; D015232:Dinoprostone