title: Effect of bisphosphonates on nitric oxide production by inflammatory activated chondrocytes.
abstract: OBJECTIVE
  Bisphosphonates have been reported to possess anti-inflammatory and cartilage protective effects in animal arthritis models but not much is known about their direct effect on chondrocytes. In this study we evaluate the effect of bisphosphonates on nitric oxide (NO) production by activated chondrocytes.
  
  
  METHODS
  Isolated bovine chondrocytes and bovine cartilage explants were used. In the second part of the study human cartilage explants (osteoarthritis (OA) and non-OA cartilage) were used. The isolated chondrocytes and cartilage explants were pre-incubated with clodronate, pamidronate or risedronate and stimulated with IL-1 and TNF-alpha (10 ng/mL, 48 h). NO production was quantified using the Griess assay.
  
  
  RESULTS
  In bovine cultures, clodronate (10(-4)mol/L) and pamidronate (10(-6)mol/L) showed a small inhibition of NO production (up to 15 % and 25% respectively), whereas risedronate had no effect. In the human cartilage cultures no effect of BPs on the NO production was detected except for the highest concentration of clodronate tested (10(-4)mol/L) which demonstrated a small enhancement (19%) in NO production reaching significance in the non-OA group.
  
  
  CONCLUSIONS
  BPs have a modest effect on NO production by inflammatory activated chondrocytes only in the higher concentrations, indicating that the clinical relevance of these effects is probably negligible.
authors.affiliation: Immunology, Allergology and Rheumatology, Faculty of Medicine, University of Antwerp, Universiteitsplein 1, Antwerp, Belgium.
authors.forename: E J
authors.initials: EJ
authors.lastname: Dombrecht
authors.forename: A J
authors.initials: AJ
authors.lastname: Schuerwegh
authors.forename: C H
authors.initials: CH
authors.lastname: Bridts
authors.forename: D G
authors.initials: DG
authors.lastname: Ebo
authors.forename: J F
authors.initials: JF
authors.lastname: Van Offel
authors.forename: W J
authors.initials: WJ
authors.lastname: Stevens
authors.forename: L S
authors.initials: LS
authors.lastname: De Clerck
mesh_terms: D000818:Animals; D050071:Bone Density Conservation Agents / Q000494:pharmacology*; D002356:Cartilage / Q000187:drug effects / Q000378:metabolism; D002417:Cattle; D002478:Cells, Cultured; D019902:Chondrocytes / Q000187:drug effects* / Q000378:metabolism*; D004002:Clodronic Acid / Q000494:pharmacology; D004164:Diphosphonates / Q000494:pharmacology*; D012968:Etidronic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D007249:Inflammation / Q000378:metabolism; D007375:Interleukin-1 / Q000494:pharmacology; D009569:Nitric Oxide / Q000096:biosynthesis*; D010003:Osteoarthritis / Q000378:metabolism; D000077268:Pamidronate; D000068296:Risedronic Acid; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
chemical_list: D050071:Bone Density Conservation Agents; D004164:Diphosphonates; D007375:Interleukin-1; D014409:Tumor Necrosis Factor-alpha; D004002:Clodronic Acid; D009569:Nitric Oxide; D000068296:Risedronic Acid; D012968:Etidronic Acid; D000077268:Pamidronate