title: Selective inhibition of cyclooxygenase (COX)-2 reverses inflammation and expression of COX-2 and interleukin 6 in rat adjuvant arthritis.
abstract: Prostaglandins formed by the cyclooxygenase (COX) enzymes are important mediators of inflammation in arthritis. The contribution of the inducible COX-2 enzyme to inflammation in rat adjuvant arthritis was evaluated by characterization of COX-2 expression in normal and arthritic paws and by pharmacological inhibition of COX-2 activity. The injection of adjuvant induced a marked edema of the hind footpads with coincident local production of PGE2. PG production was associated with upregulation of COX-2 mRNA and protein in the affected paws. In contrast, the level of COX-1 mRNA was unaffected by adjuvant injection. TNF-alpha and IL-6 mRNAs were also increased in the inflamed paws as was IL-6 protein in the serum. Therapeutic administration of a selective COX-2 inhibitor, SC-58125, rapidly reversed paw edema and reduced the level of PGE2 in paw tissue to baseline. Interestingly, treatment with the COX-2 inhibitor also reduced the expression of COX-2 mRNA and protein in the paw. Serum IL-6 and paw IL-6 mRNA levels were also reduced to near normal levels by SC-58125. Furthermore, inhibition of COX-2 resulted in a reduction of the inflammatory cell infiltrate and decreased inflammation of the synovium. Notably, the antiinflammatory effects of SC-58125 were indistinguishable from the effects observed for indomethacin. These results suggest that COX-2 plays a prominent role in the inflammation associated with adjuvant arthritis and that COX-2 derived PGs upregulate COX-2 and IL-6 expression at inflammatory sites.
authors.affiliation: Department of Inflammatory Diseases Research, G.D. Searle & Company, St. Louis, Missouri 63198, USA.
authors.forename: G D
authors.initials: GD
authors.lastname: Anderson
authors.forename: S D
authors.initials: SD
authors.lastname: Hauser
authors.forename: K L
authors.initials: KL
authors.lastname: McGarity
authors.forename: M E
authors.initials: ME
authors.lastname: Bremer
authors.forename: P C
authors.initials: PC
authors.lastname: Isakson
authors.forename: S A
authors.initials: SA
authors.lastname: Gregory
mesh_terms: D000818:Animals; D001169:Arthritis, Experimental / Q000276:immunology / Q000503:physiopathology*; D001483:Base Sequence; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology*; D017931:DNA Primers; D003907:Dexamethasone / Q000494:pharmacology; D015232:Dinoprostone / Q000096:biosynthesis; D015870:Gene Expression / Q000187:drug effects; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D007213:Indomethacin / Q000494:pharmacology; D007249:Inflammation / Q000517:prevention & control; D015850:Interleukin-6 / Q000096:biosynthesis*; D007527:Isoenzymes / Q000096:biosynthesis; D007596:Joints / Q000187:drug effects / Q000473:pathology / Q000503:physiopathology; D008297:Male; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D011451:Prostaglandin-Endoperoxide Synthases / Q000096:biosynthesis*; D011720:Pyrazoles / Q000494:pharmacology* / Q000627:therapeutic use; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D011917:Rats, Inbred Lew; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis
chemical_list: D016861:Cyclooxygenase Inhibitors; D017931:DNA Primers; D015850:Interleukin-6; D007527:Isoenzymes; D011720:Pyrazoles; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; C090859:1-((4-methylsulfonyl)phenyl)-3-trifluoromethyl-5-(4-fluorophenyl)pyrazole; D003907:Dexamethasone; D011451:Prostaglandin-Endoperoxide Synthases; D015232:Dinoprostone; D007213:Indomethacin