title: Effects of sodium hyaluronate and methylprednisolone acetate on proteoglycan synthesis in equine articular cartilage explants.
abstract: OBJECTIVE
  To determine effects of sodium hyaluronate (HA) on corticosteroid-induced cartilage matrix catabolism in equine articular cartilage explants.
  
  
  METHODS
  30 articular cartilage explants from fetlock joints of 5 adult horses without joint disease.
  
  
  METHODS
  Articular cartilage explants were treated with control medium or medium containing methylprednisolone acetate (MPA; 0.05, 0.5, or 5.0 mg/mL), HA (0.1, 1.0, or 1.5 mg/mL), or both. Proteoglycan (PG) synthesis was measured by incorporation of sulfur 35-labeled sodium sulphate into PGs, and PG degradation was measured by release of radiolabeled PGs into the medium. Total glycosaminoglycan (GAG) content in media and explants and total explant DNA were determined.
  
  
  RESULTS
  Methylprednisolone acetate caused a decrease in PG synthesis, whereas HA had no effect. Only the combination of MPA at a concentration of 0.05 mg/mL and HA at a concentration of 1.0 mg/mL increased PG synthesis, compared with control explants. Methylprednisolone acetate increased degradation of newly synthesized PGs into the medium, compared with control explants, and HA alone had no effect. Hyaluronate had no effect on MPA-induced PG degradation and release into media. Neither MPA alone nor HA alone had an effect on total cartilage GAG content. Methylprednisolone acetate caused an increase in release of GAG into the medium at 48 and 72 hours after treatment. In combination, HA had no protective effect on MPA-induced GAG release into the medium. Total cartilage DNA content was not affected by treatments.
  
  
  CONCLUSIONS
  Our results indicate that HA addition has little effect on corticosteroid-induced cartilage matrix PG catabolism in articular cartilage explants.
authors.affiliation: College of Veterinary Medicine, University of Illinois, 1008 W Hazelwood Dr, Urbana, IL 61802, USA.
authors.forename: Aimie J
authors.initials: AJ
authors.lastname: Doyle
authors.forename: Allison A
authors.initials: AA
authors.lastname: Stewart
authors.forename: Peter D
authors.initials: PD
authors.lastname: Constable
authors.forename: Jo Ann C
authors.initials: JA
authors.lastname: Eurell
authors.forename: David E
authors.initials: DE
authors.lastname: Freeman
authors.forename: Dominique J
authors.initials: DJ
authors.lastname: Griffon
mesh_terms: D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D002358:Cartilage, Articular / Q000187:drug effects* / Q000378:metabolism; D019902:Chondrocytes / Q000187:drug effects / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D015870:Gene Expression; D006025:Glycosaminoglycans / Q000378:metabolism; D006736:Horses / Q000378:metabolism*; D006820:Hyaluronic Acid / Q000494:pharmacology*; D066298:In Vitro Techniques; D008775:Methylprednisolone / Q000031:analogs & derivatives* / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D000077555:Methylprednisolone Acetate; D011509:Proteoglycans / Q000096:biosynthesis*
chemical_list: D000893:Anti-Inflammatory Agents; D006025:Glycosaminoglycans; D011509:Proteoglycans; D000077555:Methylprednisolone Acetate; D006820:Hyaluronic Acid; D004247:DNA; D008775:Methylprednisolone