title: Effects of oral administration of phenylbutazone to horses on in vitro articular cartilage metabolism.
abstract: OBJECTIVE
  To evaluate the effects of orally administered phenylbutazone on proteoglycan synthesis and chondrocyte inhibition by IL-1beta in articular cartilage explants of horses.
  
  
  METHODS
  11 healthy 1- to 2-year-old horses.
  
  
  METHODS
  Horses were randomly assigned to the control (n = 5) or treated group (4.4 mg of phenylbutazone/kg of body weight, p.o., q 12 h; n = 6). Articular cartilage specimens were collected before treatment was initiated (day 0), after 14 days of treatment, and 2 weeks after cessation of treatment (day 30). Proteoglycan synthesis and stromelysin concentration in cartilage extracts were assessed after 72 hours of culture in medium alone or with recombinant human interleukin-1beta (IL-1beta; 0.1 ng/ml).
  
  
  RESULTS
  On day 0, proteoglycan synthesis was significantly less in cartilage explants cultured in IL-1beta, compared with medium alone. Mean proteoglycan synthesis in explants collected on days 14 and 30 was significantly less in treated horses, compared with controls. However, incubation of explants from treated horses with IL-1beta did not result in a further decrease in proteoglycan synthesis. Significant differences in stromelysin concentration were not detected between or within groups.
  
  
  CONCLUSIONS
  Oral administration of phenylbutazone for 14 days significantly decreased proteoglycan synthesis in articular culture explants from healthy horses to a degree similar to that induced by in vitro exposure to IL-1beta. Phenylbutazone should be used judiciously in athletic horses with osteoarthritis, because chronic administration may suppress proteoglycan synthesis and potentiate cartilage damage.
authors.affiliation: Department of Veterinary Clinical Sciences, The Ohio State University, Columbus 43210, USA.
authors.forename: L A
authors.initials: LA
authors.lastname: Beluche
authors.forename: A L
authors.initials: AL
authors.lastname: Bertone
authors.forename: D E
authors.initials: DE
authors.lastname: Anderson
authors.forename: C
authors.initials: C
authors.lastname: Rohde
mesh_terms: D000284:Administration, Oral; D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage / Q000494:pharmacology*; D002358:Cartilage, Articular / Q000187:drug effects* / Q000378:metabolism; D006736:Horses / Q000378:metabolism*; D007375:Interleukin-1 / Q000494:pharmacology; D019278:Matrix Metalloproteinase 3 / Q000032:analysis / Q000096:biosynthesis; D010653:Phenylbutazone / Q000008:administration & dosage / Q000494:pharmacology*; D011509:Proteoglycans / Q000032:analysis / Q000096:biosynthesis*; D011897:Random Allocation; D013582:Synovial Fluid / Q000737:chemistry
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D007375:Interleukin-1; D011509:Proteoglycans; D019278:Matrix Metalloproteinase 3; D010653:Phenylbutazone