Regulation by reactive oxygen species of interleukin-1beta, nitric oxide and prostaglandin E(2) production by human chondrocytes.

To determine the effects of two drugs, N-monomethyl-L-arginine (L-NMMA) and N-acetylcysteine (NAC), on interleukin-1beta (IL-1beta), nitric oxide (NO) and prostaglandin E(2) (PGE(2)) production by human chondrocytes. The effect of aceclofenac (ACECLO), a non-steroidal antiinflammatory drug (NSAID), was also examined. Human chondrocytes were enzymatically isolated from osteoarthritic knee cartilage and then maintained in culture in suspension for 48h in the absence or in the presence of lipopolysaccharide (LPS) (10 microg/ml), L-NMMA (0.5mM), NAC (1mM) or ACECLO (6.10(-6)M). IL-1beta and PGE(2) productions were quantified by specific immunoassays. Nitrite was measured in the culture supernatants by a spectrophotometric method based upon the Griess reaction. Cyclooxygenase-2 (COX-2), inducible NO synthase (iNOS) and IL-1beta gene expressions were quantified by transcription of mRNA followed by real time and quantitative polymerase chain reaction. COX-2 protein expression was analysed by Western blot. LPS markedly increased the expression of IL-1beta, iNOS and COX-2 genes. In parallel, NO(2) and PGE(2) amounts found in the culture supernatants were significantly enhanced whereas IL-1beta was immunologically undetectable. The addition of L-NMMA (0.5mM) fully blocked LPS-induced NO production but greatly increased PGE(2) production, suggesting a negative effect of NO on PGE(2) synthesis. Inversely, NO production was stimulated by NAC while PGE(2) production was not affected. Interestingly, NAC increased the IL-1beta and iNOS mRNA levels but did not significantly modify COX-2 mRNA expression. L-NMMA did not significantly affect the expression of IL-1beta, iNOS and COX-2. The amount of COX-2 protein did not change in the presence of the antioxidants. Finally, ACECLO fully blocked the production of PGE(2) by chondrocytes without affecting the levels of COX-2 mRNA. The stimulation of IL-1beta, NO and PGE(2) production by LPS is differentially controlled by reactive oxygen species (ROS). In fact, L-NMMA and NAC have different mechanisms of action on the regulation of NO and PGE(2) productions. L-NMMA fully inhibits NO but increases PGE(2) production whereas NAC up-regulates NO but does not modify PGE(2) synthesis. The stimulating effect of L-NMMA on PGE(2) production is not controlled at the transcriptional level. These findings suggest that antioxidant therapy could have different effects according to the oxygen radical species targeted.

Mathy-Hartert M ，Deby-Dupont GP ，Reginster JY ，Ayache N ，Pujol JP ，Henrotin YE ... -  《OSTEOARTHRITIS AND CARTILAGE》

In vitro effects of aceclofenac and its metabolites on the production by chondrocytes of inflammatory mediators.

Henrotin Y ，de Leval X ，Mathy-Hartet M ，Mouithys-Mickalad A ，Deby-Dupont G ，Dogné JM ，Delarge J ，Reginster JY ... -  《INFLAMMATION RESEARCH》

Influence of oxygen tension on nitric oxide and prostaglandin E2 synthesis by bovine chondrocytes.

Mathy-Hartert M ，Burton S ，Deby-Dupont G ，Devel P ，Reginster JY ，Henrotin Y ... -  《OSTEOARTHRITIS AND CARTILAGE》

Expression of TGF-betas and their receptors is differentially modulated by reactive oxygen species and nitric oxide in human articular chondrocytes.

To study the effects exerted by two antioxidants, N-monomethyl-L-arginine (L-NMMA), as an inhibitor of nitric oxide (NO) synthesis, and N-acetylcysteine (NAC), a reactive oxygen species (ROS) scavenger, on the expression of the major growth factor involved in cartilage repair, TGF-beta, under the three isoforms beta1, beta2 and beta3, and the receptors I and II of this factor, using lipopolysaccharide (LPS)-treated human chondrocytes in culture. Suspension cultures of human chondrocytes derived from the knee of osteoarthritic patients were treated for 48 h with lipopolysaccharide (LPS) (10 microg/ml), L-NMMA (0.5 mM) or NAC (1 mM). Nitrite levels were assayed on the culture media using the Griess spectrophotometric method. After total RNA extraction, the expression of inducible NO synthase (iNOS), TGF-beta1, TGF-beta2, TGF-beta3, TGF-beta receptors I and II, was determined by semi-quantitative polymerase chain-reaction (RT-PCR). LPS induced a dramatic increase of both NO production and iNOS mRNA level. The addition of L-NMMA (0.5 mM) abolished NO production without affecting iNOS mRNA levels. In contrast NAC (1 mM) strongly synergized with LPS to stimulate NO synthesis. LPS treatment did not significantly alter TGF-beta1 expression whereas L-NMMA inhibited its production. TGF-beta2 mRNA level was decreased by LPS and was not changed in the presence of L-NMMA. On the other hand, NAC was capable of counteracting the LPS-induced inhibition of TGF-beta2 expression. TGFbeta3 mRNA level was markedly reduced by LPS alone, or with both L-NMMA and NAC. Finally, the expression of TGF-betaRI was slightly increased in the presence of combined LPS and L-NMMA or NAC whereas that of TGFbeta-RII was reduced in the same conditions. The modulation of TGF-beta system was found to be differentially controlled by NO and ROS productions. Indeed, the control exerted on TGF-beta expression varied according to the isoform: TGF-beta1 mRNA level depends on NO whereas that of TGF-beta2 is regulated by ROS and TGF-beta3 seems to be unaffected by both of them. The expression of TGF-beta receptors appeared to be modulated by NO and ROS levels. The relevance of the present findings to osteoarthritis (OA) physiopathology and the potential use of antioxidant therapy to treat this disease are discussed.

Ayache N ，Boumediene K ，Mathy-Hartert M ，Reginster JY ，Henrotin Y ，Pujol JP ... -  《OSTEOARTHRITIS AND CARTILAGE》

Inhibitory effect of Buthus martensi Karsch extracts on interleukin-1beta-induced expression of nitric oxide (NO) synthase and production of NO in human chondrocytes and LPS-induced NO and prostaglandin E2 production in mouse peritoneal macrophages.

Kim KS ，Cho HS ，Lee SD ，Kim KH ，Cho JY ，Chung KH ，Lee YC ，Moon SK ，Kim CH ... -  《TOXICOLOGY IN VITRO》