title: Gross, histologic, and gene expression characteristics of osteoarthritic articular cartilage of the metacarpal condyle of horses.
abstract: OBJECTIVE
  To identify patterns and correlations of gross, histologic, and gene expression characteristics of articular cartilage from horses with osteoarthritis.
  
  
  METHODS
  10 clinically normal horses and 11 horses with osteoarthritis of the metacarpal condyles.
  
  
  METHODS
  Metacarpophalangeal joints were opened and digitally photographed, and gross lesions were scored and quantified. Representative cartilage specimens were stained for histologic scoring. Total RNA from dorsal and palmar articular surfaces was processed on an equine gene expression microarray.
  
  
  RESULTS
  Histologic scores were greater in both regions of osteoarthritic joints, compared with corresponding regions in control joints. Cartilage from the palmar aspect of diseased joints had the highest histologic scores of osteoarthritic sites or of either region in control joints. A different set of genes for dorsal and palmar osteoarthritis was identified for high and low gene expression. Articular cartilage from the dorsal region had surface fraying and greater expression of genes coding for collagen matrix components and proteins with anti-apoptotic function, compared with control specimens. Articular cartilage from the palmar region had greater fraying, deep fissures, and less expression of genes coding for glycosaminoglycan matrix formation and proteins with anti-apoptotic function, compared with cartilage from disease-free joints and the dorsal aspect of affected joints.
  
  
  CONCLUSIONS
  Metacarpal condyles of horses with naturally occurring osteoarthritis had an identifiable and regional gene expression signature with typical morphologic features.
authors.affiliation: Comparative Orthopedic Research Laboratories, Department of Veterinary Clinical Sciences, The Ohio State University, Columbus, 43210, USA.
authors.forename: Katie J
authors.initials: KJ
authors.lastname: Smith
authors.forename: Alicia L
authors.initials: AL
authors.lastname: Bertone
authors.forename: Stephen E
authors.initials: SE
authors.lastname: Weisbrode
authors.forename: Michael
authors.initials: M
authors.lastname: Radmacher
mesh_terms: D000818:Animals; D002358:Cartilage, Articular / Q000378:metabolism* / Q000473:pathology; D005552:Forelimb / Q000378:metabolism* / Q000473:pathology; D020869:Gene Expression Profiling / Q000662:veterinary*; D005786:Gene Expression Regulation; D006734:Horse Diseases / Q000378:metabolism* / Q000473:pathology; D006736:Horses; D010003:Osteoarthritis / Q000378:metabolism / Q000473:pathology / Q000662:veterinary*