Stimulation of cyclooxygenase-2-activity by nitric oxide-derived species in rat chondrocyte: lack of contribution to loss of cartilage anabolism

Biochem Pharmacol. 2001 Apr 15;61(8):965-78. doi: 10.1016/s0006-2952(01)00559-7.


Cross-talk between inducible nitric oxide synthase (NOS II) and cyclooxygenase-2 (COX-2) was investigated in rat chondrocytes. In monolayers, interleukin-1beta (IL-1beta) induced COX-2 and NOS II expression in a dose- and time-dependent manner, to produce high prostaglandin E(2) (PGE(2)) and nitrite (NO(2)(-)) levels in an apparently coordinated fashion. COX-2 mRNA was induced earlier (30 min. versus 4 hr) and less markedly (4-fold versus 12-fold at 24 hr) than NOS II, and was poorly affected by the translational inhibitor cycloheximide (CHX). IL-1beta did not stabilize COX-2 mRNA in contrast to CHX. Indomethacin and NS-398 lacked any effect on NO(2)(-) levels whereas L-NMMA and SMT reduced PGE(2) levels at concentration inhibiting NO(2)(-) production from 50 to 90%, even when added at a time allowing a complete expression of both enzymes (8 hr). Basal COX activity was unaffected by NO donors. The SOD mimetic, CuDips inhibited COX-2 activity by more than 75% whereas catalase did not. Inhibition of COX-2 by CuDips was not sensitive to catalase, consistent with a superoxide-mediated effect. In tridimensional culture, IL-1beta inhibited radiolabelled sodium sulphate incorporation while stimulating COX-2 and NOS II activities. Cartilage injury was corrected by L-NMMA or CuDips but not by NSAIDs, consistent with a peroxynitrite-mediated effect. These results show that in chondrocytes: (i) COX2 and NOS II genes are induced sequentially and distinctly by IL-1beta; (ii) COX-1 and COX-2 activity are affected differently by NO-derived species; (iii) peroxynitrite accounts likely for stimulation of COX-2 activity and inhibition of proteoglycan synthesis induced by IL-1beta.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cartilage / cytology
  • Cartilage / metabolism
  • Chondrocytes / drug effects*
  • Chondrocytes / enzymology
  • Chondrocytes / metabolism
  • Cyclooxygenase 2
  • Cyclooxygenase 2 Inhibitors
  • Cyclooxygenase Inhibitors / pharmacology
  • Dose-Response Relationship, Drug
  • Enzyme Activation / drug effects
  • Enzyme Inhibitors / pharmacology
  • Gene Expression Regulation, Enzymologic / drug effects
  • Indomethacin / pharmacology
  • Interleukin-1 / metabolism
  • Interleukin-1 / pharmacology*
  • Isoenzymes / antagonists & inhibitors
  • Isoenzymes / genetics
  • Isoenzymes / metabolism*
  • Male
  • Nitric Oxide Synthase / antagonists & inhibitors
  • Nitric Oxide Synthase / genetics
  • Nitric Oxide Synthase / metabolism
  • Nitric Oxide Synthase Type II
  • Nitrites / metabolism
  • Nitrobenzenes / pharmacology
  • Prostaglandin-Endoperoxide Synthases / genetics
  • Prostaglandin-Endoperoxide Synthases / metabolism*
  • Proteoglycans / biosynthesis
  • Proteoglycans / drug effects
  • Rats
  • Rats, Wistar
  • Sulfonamides / pharmacology
  • Thiourea / pharmacology
  • omega-N-Methylarginine / pharmacology


  • Cyclooxygenase 2 Inhibitors
  • Cyclooxygenase Inhibitors
  • Enzyme Inhibitors
  • Interleukin-1
  • Isoenzymes
  • Nitrites
  • Nitrobenzenes
  • Proteoglycans
  • Sulfonamides
  • methylthioisourea
  • N-(2-cyclohexyloxy-4-nitrophenyl)methanesulfonamide
  • omega-N-Methylarginine
  • Nitric Oxide Synthase
  • Nitric Oxide Synthase Type II
  • Cyclooxygenase 2
  • Prostaglandin-Endoperoxide Synthases
  • Thiourea
  • Indomethacin