PT  - JOURNAL ARTICLE
AU  - T Sadowski
AU  - J Steinmeyer
TI  - Minocycline inhibits the production of inducible nitric oxide synthase in articular chondrocytes.
DP  - 2001 Feb 01
TA  - The Journal of Rheumatology
PG  - 336--340
VI  - 28
IP  - 2
4099  - http://www.jrheum.org/content/28/2/336.short
4100  - http://www.jrheum.org/content/28/2/336.full
SO  - J Rheumatol2001 Feb 01; 28
AB  - OBJECTIVE: To determine the in vitro effects of tetracyclines and nonsteroidal antiiflammatory drugs on interleukin 1alpha (IL-1alpha) induced NO production and biosynthesis of inducible NO synthase (iNOS) by articular chondrocytes. METHODS: Bovine chondrocytes were cultured in alginate beads. Cells were treated with IL-lalpha in the presence or absence of drugs at various concentrations. Expression of mRNA for iNOS was analyzed by reverse transcription polymerase chain reaction-ELISA. Protein synthesis of iNOS was determined by immunoprecipitation. NO production was taken as a measure for the activity of the enzyme. RESULTS: Minocycline dose dependently reduced IL-1 stimulated NO production by inhibition of the mRNA expression (IC50 = 69.9 microM) and protein synthesis (IC50 = 37.11 microM) of iNOS. Diclofenac-Na at a concentration of 10 microM only weakly reduced nitrite accumulation and mRNA expression of iNOS. No effects were observed for tetracycline, doxycycline, and meloxicam. CONCLUSION: Inhibition of iNOS in articular chondrocytes may be a new mechanism by which minocycline could exert its beneficial effects in the treatment of joint diseases.