Nitric oxide mediated effect of cyclo-oxygenase inhibitors

ABSTRACT

Non-Steroidal anti-inflammatory drugs [NSAIDS] have long been used as anti-inflammatory agents, yet their mode of action is not entirely clear. The inhibitory effects of NSAIDS on prostaglandin production can only partly explain their anti-inflammatory actions. This study was aimed at defining the role of cyclo-oxygenase [COX] inhibitors on nitric oxide [NO] production in murine macrophages in vitro. METHODS: Murine macrophages were obtained from the peritoneum and after exposure, in vitro to lipopolysaccharide [LPS] produced nitrite, measured after 24 hours by Griess reaction. The macrophages were pre-incubated with aspirin or indomethacin before activation with LPS. Treatment with aspirin resulted in an increase in nitric oxide production. A similar response was obtained with indomethacin treatment. This study shows that COX inhibitors significantly increase NO production in murine macrophages in vitro and this may be one of the mechanisms by which they exert their anti-inflammatory effects