ab21509

Combined inhibition of nitrergic and prostanoid pathways in J774 macrophages

S.M. Day, J.S. McLean, J.C. Lockhart, W.R. Ferrell¹

Biological Sciences, University of Paisley, Paisley; ¹Division of Immunology, Infection & Inflammation, Centre for Rheumatic Diseases, Royal Infirmary Glasgow, UK.

ABSTRACT
Objectives
Nitric oxide and prostaglandins are both implicated in the pathogenesis of inflammatory conditions such as rheumatoid arthritis (RA). The hypothesis that simultaneous inhibition of nitric oxide synthase (NOS) and cyclooxygenase (COX) was more effective than inhibition of either enzyme alone was tested.

Methods
J774 macrophages were pre-incubated with L-NAME and/or indomethacin, prior to activation with LPS 10 mg/ml).

Results
LPS significantly increased NO2-, PGE2 and TNF-a levels by 24h. Quantitative real-time PCR demonstrated a dose-dependent reduction in the expression of COX-2 in the presence of increasing doses of L-NAME. NO₂- and PGE2 production were inhibited in a dose-dependent manner by either indomethacin or L-NAME. Combined administration of L-NAME and indomethacin produced a significantly greater inhibition of NO2- and PGE2 than either inhibitor alone.

Conclusion
The data supports the therapeutic potential of combined inhibition of the prostanoid and nitrergic systems as an anti-inflammatory treatment strategy and supports the progression of this work into models of arthritis.

Key words
Inflammation, nitric oxide (NO), prostaglandin E2 (PGE2), tumour necrosis factor-a (TNF-a).

This work was supported by University of Paisley Research funds.
Please address correspondence and reprint requests to: Prof. J.C. Lockhart, Department of Biological Sciences, University of Paisley, Paisley PA1 2BE, Scotland.
E-mail: john.lockhart@paisley.ac.uk