title: The use of intra-articular Na-hyaluronate as a potential chondroprotective device in experimentally induced acute articular cartilage injury and repair in rabbits.
abstract: OBJECTIVE
  This study examined if viscosupplementation from intra-articular administration of a commercially available form of hyaluronan (HA) could promote the restoration of proteoglycan (PG) depletion induced by chymopapain and then if the repair could be maintained once HA treatment was discontinued.
  
  
  METHODS
  Animals received cartilage injury with intra-articular chymopapain (2.0 mg) followed by weekly treatment with intra-articular HA. HA treated animals were compared to injured animals with no treatment, contralateral untreated joints and joints from normal controls. The effect of intra-articular HA alone on articular cartilage was also examined.
  
  
  RESULTS
  Serum keratan sulfate levels confirmed degradation of the cartilage PGs in the chymopapain-injected knees. Intra-articular chymopapain resulted in marked loss of PGs. There were no significant differences among the control groups (untreated control, HA/800 treatment only). HA treatment did not affect the loss of PGs caused by chymopapain after 42 days. However, in animals receiving chymopapain injury followed by weekly HA treatment for 42 days and then 42 days of free cage activity without HA, cartilage PG contents were significantly increased. Intra-articular HA alone had no effect on the articular cartilage.
  
  
  CONCLUSIONS
  The results in the present study suggest a potential protective effect of HA on chymopapain-induced acute articular cartilage injury in rabbits that, in time, permits damaged cartilage to resynthesize matrix PGs after the HA treatment is discontinued.
authors.affiliation: Department of Anatomy, Rush Medical College at Rush Presbyterian St. Luke's Medical Center, Chicago, IL 60612, USA. james_m_williams@rush.edu
authors.forename: James M
authors.initials: JM
authors.lastname: Williams
authors.forename: Vineeta
authors.initials: V
authors.lastname: Rayan
authors.forename: D Rick
authors.initials: DR
authors.lastname: Sumner
authors.forename: Eugene J-M A
authors.initials: EJ
authors.lastname: Thonar
mesh_terms: D000818:Animals; D002358:Cartilage, Articular / Q000187:drug effects* / Q000293:injuries / Q000378:metabolism; D002917:Chymopapain / Q000008:administration & dosage / Q000494:pharmacology; D004195:Disease Models, Animal; D006614:Hindlimb; D006820:Hyaluronic Acid / Q000008:administration & dosage / Q000494:pharmacology*; D007270:Injections, Intra-Articular; D007632:Keratan Sulfate / Q000097:blood; D008297:Male; D020011:Protective Agents / Q000008:administration & dosage / Q000494:pharmacology*; D011509:Proteoglycans / Q000378:metabolism; D011817:Rabbits; D014783:Viscosity; D014945:Wound Healing / Q000187:drug effects*
chemical_list: D020011:Protective Agents; D011509:Proteoglycans; D006820:Hyaluronic Acid; D007632:Keratan Sulfate; D002917:Chymopapain