title: In vitro effects of diacerhein and rhein on interleukin 1 and tumor necrosis factor-alpha systems in human osteoarthritic synovium and chondrocytes.
abstract: OBJECTIVE
  To evaluate the in vitro effects of diacerhein, a new drug for the treatment of osteoarthritis (OA), and its active metabolite, rhein, on interleukin 1beta (IL-1beta) and tumor necrosis factor-alpha (TNF-alpha) synthesis and expression in human OA synovial membrane, and on the IL-1beta and TNF-alpha receptors on human OA chondrocytes.
  
  
  METHODS
  Levels of IL-1beta and TNF-alpha were determined using specific ELISA in culture medium of human synovial membrane explants incubated in the presence of 1 microg/ml of lipopolysaccharide with or without therapeutic concentrations of diacerhein (1.4, 2.7, 5.4 x 10(-5) M) and rhein (1.7, 3.5, 7.0 x 10(-5) M). IL-1beta mRNA level was quantitated by Northern blotting. Using radioligand binding experiments, we determined the effects of these agents on the density and affinity of chondrocyte IL-1 and TNF receptors.
  
  
  RESULTS
  IL-1beta synthesis was significantly inhibited by diacerhein and rhein, with maximum inhibition at 5.4 x 10(-5) M for diacerhein (p < 0.02) and 3.5 x 10(-5) M for rhein (p < 0.05). The effect of both agents on IL-1beta was found to be translational and/or post-translational, judging by the absence of effect on gene expression level. Both agents produced dose and time dependent decreases in the number of IL-1 receptors (IL-1R) on OA chondrocytes. This effect was mediated through a reduction in the level of the type I IL-1R as shown by experiments using a blocking monoclonal antibody against this receptor type. Both agents also markedly reduced the IL-1 induced synthesis and expression of stromelysin 1. Neither diacerhein nor rhein significantly affected the level of synthesis of TNF-alpha or the level of TNF-R.
  
  
  CONCLUSIONS
  Diacerhein and rhein can effectively inhibit the synthesis of IL-1beta on human OA synovium, as well as the action of this cytokine at the cartilage level, by reducing the number of chondrocyte IL-1R. The effects of these agents seemed "selective" to the IL-1 system.
authors.affiliation: Unité de recherche en arthrose, Centre de recherche L.C. Simard, Campus Notre-Dame, Centre hospitalier universitaire de Montréal, Québec, Canada.
authors.forename: J
authors.initials: J
authors.lastname: Martel-Pelletier
authors.forename: F
authors.initials: F
authors.lastname: Mineau
authors.forename: F C
authors.initials: FC
authors.lastname: Jolicoeur
authors.forename: J M
authors.initials: JM
authors.lastname: Cloutier
authors.forename: J P
authors.initials: JP
authors.lastname: Pelletier
mesh_terms: D000368:Aged; D000880:Anthraquinones / Q000494:pharmacology*; D015152:Blotting, Northern; D002478:Cells, Cultured; D019902:Chondrocytes / Q000187:drug effects / Q000378:metabolism*; D046508:Culture Techniques; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D006801:Humans; D007375:Interleukin-1 / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000494:pharmacology; D008297:Male; D019278:Matrix Metalloproteinase 3 / Q000378:metabolism; D008875:Middle Aged; D010003:Osteoarthritis / Q000378:metabolism*; D017472:Receptors, Interleukin-1 / Q000378:metabolism; D018124:Receptors, Tumor Necrosis Factor / Q000378:metabolism; D013583:Synovial Membrane / Q000187:drug effects / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*
chemical_list: D000880:Anthraquinones; D004791:Enzyme Inhibitors; D007375:Interleukin-1; D008070:Lipopolysaccharides; D017472:Receptors, Interleukin-1; D018124:Receptors, Tumor Necrosis Factor; D014409:Tumor Necrosis Factor-alpha; C025292:diacerein; D019278:Matrix Metalloproteinase 3; C020491:rhein