title: Synovial fluid chondroitin sulphate indicates abnormal joint metabolism in asymptomatic osteochondritic horses.
abstract: BACKGROUND
  Alternative methods to evaluate the joint condition in asymptomatic osteochondrosis dissecans (OCD) and other joint diseases may be useful.
  
  
  OBJECTIVE
  To investigate possible changes in synovial fluid composition that may lead to joint conditions in asymptomatic OCD, in mature horses.
  
  
  METHODS
  Animals aged >2 years, of different breeds, with OCD in the intermediate ridge of distal tibia, symptomatic or not, were studied. Synovial fluid samples (10 healthy; 11 asymptomatic OCD; 25 symptomatic OCD) were collected by arthroscopy from 29 horses. Glycosaminoglycans (GAGs) were analysed by a combination of agarose gel electrophoresis and enzymatic degradation with specific GAG lyases. The viscosity, white blood cell (WBC) count, protein concentration and hyaluronic acid (HA) molecular weight were also determined.
  
  
  RESULTS
  The method used here to analyse synovial fluid GAGs is reliable, reproducible and specific. The main synovial fluid GAGs are HA and chondroitin sulphate (CS), 93% and 7% respectively in normal horses. In symptomatic OCD, the concentrations of both increased (expressed as GAG/urea ratios), but CS increased more. The CS increased also in asymptomatic OCD. An inflammatory reaction was suggested by the increased WBC counts in OCD. The molecular weight of the synovial fluid HA was reduced in OCD, explaining the lower viscosity observed.
  
  
  CONCLUSIONS
  The increased CS in synovial fluid of OCD joints in mature horses suggests that the synovial fluid CS and the WBC count are good markers of the joint conditions, allowing the identification of pathological phase in joint diseases.
  
  
  CONCLUSIONS
  The analysis of synovial fluid GAGs shows that cartilage damage occurs even in asymptomatic OCD, implying that arthroscopic removal of osteochondral fragments should be performed even in asymptomatic OCD.
authors.affiliation: Departamento de Cirurgia, Faculdade de Medicina Veterinária e Zootecnia, USP, São Paulo, Brazil.
authors.forename: T S L
authors.initials: TS
authors.lastname: Machado
authors.forename: L C L
authors.initials: LC
authors.lastname: Correia da Silva
authors.forename: R Y A
authors.initials: RY
authors.lastname: Baccarin
authors.forename: Y M
authors.initials: YM
authors.lastname: Michelacci
mesh_terms: D000818:Animals; D002809:Chondroitin Sulfates / Q000737:chemistry* / Q000378:metabolism; D005260:Female; D006734:Horse Diseases / Q000188:drug therapy*; D006736:Horses; D006820:Hyaluronic Acid / Q000737:chemistry / Q000378:metabolism; D007596:Joints / Q000378:metabolism*; D008297:Male; D055034:Osteochondrosis / Q000378:metabolism / Q000473:pathology / Q000662:veterinary*; D011506:Proteins / Q000737:chemistry / Q000378:metabolism; D013582:Synovial Fluid / Q000737:chemistry*; D014508:Urea / Q000737:chemistry / Q000378:metabolism; D014783:Viscosity
chemical_list: D011506:Proteins; D014508:Urea; D006820:Hyaluronic Acid; D002809:Chondroitin Sulfates