title: Effects of hyaluronan on proteoglycan content of osteoarthritic chondrocytes in vitro.
abstract: OBJECTIVE
  To investigate the effect of hyaluronic acid (HA) on proteoglycan (PG) concentration in alginate cultures of human osteoarthritic chondrocytes and to analyze whether HA exhibit anti-degradative effects in the presence of the cytokine IL-1beta.
  
  
  METHODS
  Cartilage samples from ten patients with osteoarthritis of the knee were harvested and chondrocytes were cultivated in alginate beads. Four groups were cultured: control group with and without IL-1beta (500 pg/ml) and HA group (100 microg/ml) with and without IL-1beta (500 pg/ml). PG concentration was estimated by a dimethylmethylene blue assay. To assess cell proliferation, we measured DNA content fluorometrically.
  
  
  RESULTS
  The proliferation rate (DNA) was unchanged in all culture groups. In the control-group PG/DNA (ng/ng) concentration was 27.1 +/- 7.2. Supplementation of the medium with HA decreased PG concentration to 25.3 +/- 6.9 (p < 0.05). After administration of IL-1beta PG/DNA concentration dropped to 23.1 +/- 6.0 (p < 0.01). By contrast HA treatment of IL-1beta stimulated chondrocytes did not further decrease PG concentration (23.9 +/- 6.1). In fact the negative effect of isolated HA application was inverted if HA was given with IL-1beta (p < 0.05).
  
  
  CONCLUSIONS
  In osteoarthritic chondrocytes cultured phenotypically stable, HA could exhibit protective effects only in the presence of the degradative cytokine IL-1beta. Thus, the reported anti-inflammatory effects of HA to cartilage matrix seem to be more indirect by blocking degradative effects of cytokines to the matrix.
authors.affiliation: Department of Orthopaedic Surgery (RKU), University of Ulm, Germany. johannes.stoeve@medizin.uni-ulm.de
authors.forename: Johannes
authors.initials: J
authors.lastname: Stöve
authors.forename: Christina
authors.initials: C
authors.lastname: Gerlach
authors.forename: Klaus
authors.initials: K
authors.lastname: Huch
authors.forename: Klaus-Peter
authors.initials: KP
authors.lastname: Günther
authors.forename: Wolfhart
authors.initials: W
authors.lastname: Puhl
authors.forename: Hanns-Peter
authors.initials: HP
authors.lastname: Scharf
mesh_terms: D000368:Aged; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D019902:Chondrocytes / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D004357:Drug Synergism; D005260:Female; D006801:Humans; D006820:Hyaluronic Acid / Q000494:pharmacology*; D007375:Interleukin-1 / Q000494:pharmacology; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis / Q000378:metabolism* / Q000473:pathology; D011509:Proteoglycans / Q000037:antagonists & inhibitors / Q000378:metabolism*
chemical_list: D007375:Interleukin-1; D011509:Proteoglycans; D006820:Hyaluronic Acid