title: Paeoniflorin inhibits function of synoviocytes pretreated by rIL-1α and regulates EP4 receptor expression.
abstract: BACKGROUND
  To investigate the effect of the Paeoniflorin (Pae), a main active component of total glucosides of paeony (TGP) extracted from the root of Paeonia lactiflora, on regulation of synoviocytes cultured from rats collagen-induced arthritis (CIA) in vitro.
  
  
  METHODS
  CIA was induced in male Sprague-Dawley rats immunized with chicken type II collagen (CCII) in Freund's complete adjuvant. The levels of interleukin-1 (IL-1), tumor necrosis factor α (TNF-α), prostaglandin E(2) (PGE(2)) and cyclic adenosine monophosphate (cAMP) were measured by radioimmunoassay. The proliferation responses was determined by the 3-(4,5-2dimethylthiazal-2yl) 2,5-diphenyltetrazoliumbromide (MTT) assay. Expression of E-prostanoid (EP(4)) receptor was detected by Western blotting technique.
  
  
  RESULTS
  Treatment of Pae (2.5, 12.5, 62.5 μg/ml) significantly decreased the production of IL-1 and TNF-α. Recombinant interleukin-1 (rIL-1α) (10 ng/ml) apparently stimulated synoviocyte, thymocyte and splenocyte proliferation, and Pae (12.5, 62.5 μg/ml) inhibited abnormal proliferation responses stimulated by rIL-1α. Moreover, rIL-1α time- and concentration-dependently increased production of PGE(2). The production of PGE(2) produced by synoviocytes from CIA rats significantly inhibited by administration of Pae (12.5, 62.5 μg/ml). rIL-1α (10 ng/ml) decreased cAMP of synoviocytes cells treated for 24h. Similarly rIL-1α (0.1, 1, 10 ng/ml) induced a concentration-dependent decrease in the production of cAMP at 24h. Pae (12.5, 62.5 μg/ml) increased the production of cAMP in synoviocytes. The immunoblot, Pae (12.5, 62.5 μg/ml) apparently increased the expression of EP(4) receptor in synoviocytes stimulated by rIL-1α (10 ng/ml).
  
  
  CONCLUSIONS
  The present study indicates that Pae might exert its anti-inflammatory effects through suppressing synoviocytes function and regulating immune cells responses in CIA rats, which might be associated with its ability to up-regulate the E-prostanoid (EP(4)) receptor protein expression and modulate intracellular cAMP level.
authors.affiliation: Institute of Clinical Pharmacology, Anhui Medical University, Key Laboratory of Anti-inflammatory and Immunopharmacology of Education Ministry, Meishan Road, Hefei 230032, Anhui Province, China. changyan318@sohu.com
authors.forename: Yan
authors.initials: Y
authors.lastname: Chang
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.forename: Chun
authors.initials: C
authors.lastname: Wang
authors.forename: Xiao-Yi
authors.initials: XY
authors.lastname: Jia
authors.forename: Wei
authors.initials: W
authors.lastname: Wei
mesh_terms: D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D001169:Arthritis, Experimental / Q000139:chemically induced / Q000188:drug therapy* / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D001565:Benzoates / Q000494:pharmacology*; D015153:Blotting, Western; D001952:Bridged-Ring Compounds / Q000494:pharmacology*; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D024043:Collagen Type II; D000242:Cyclic AMP / Q000378:metabolism; D015232:Dinoprostone / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005960:Glucosides / Q000494:pharmacology*; D053582:Interleukin-1alpha / Q000378:metabolism*; D008297:Male; D039821:Monoterpenes; D011863:Radioimmunoassay; D051381:Rats; D017207:Rats, Sprague-Dawley; D058309:Receptors, Prostaglandin E, EP4 Subtype / Q000187:drug effects* / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D013154:Spleen / Q000187:drug effects / Q000276:immunology; D013583:Synovial Membrane / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D060168:Thymocytes / Q000187:drug effects / Q000276:immunology; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D015854:Up-Regulation; D006027:Glycosides
chemical_list: D000893:Anti-Inflammatory Agents; D001565:Benzoates; D001952:Bridged-Ring Compounds; D024043:Collagen Type II; D000242:Cyclic AMP; D015232:Dinoprostone; D005960:Glucosides; D053582:Interleukin-1alpha; D039821:Monoterpenes; D058309:Receptors, Prostaglandin E, EP4 Subtype; D011994:Recombinant Proteins; D014409:Tumor Necrosis Factor-alpha; C545652:Ptger4 protein, rat; C015423:peoniflorin; D006027:Glycosides