Modulation of oxidant status by meloxicam in experimentally induced arthritis

Meloxicam is a new non-steroidal anti-inflammatory drug, that possesses a s elective inhibition of the inducible isoform of cyclooxygenase enzyme (COX- 2) relative to the constitutive one, COX-1. Oxidative stress has been docum ented to be involved in the aetiology of many pathological conditions. The present study aims to further explore the relationship between free radical generation and the inflammatory process, and extends more to investigate t he effect of meloxicam on the oxidant status in experimentally induced arth ritis, namely, Freund's adjuvant-induced arthritis in rats. Results of the present investigation revealed that animals inoculated with Freund's comple te adjuvant showed a biphasic response regarding changes in the right hind paw oedema volume. During the chronic phase of the disease, arthritic anima ls showed an elevated plasma level of lipid peroxides, enhanced blood gluta thione peroxidase activity, with depletion of plasma total thiols and album in; while no significant effects have been observed on erythrocytic superox ide dismutase activity and plasma total proteins content, as compared to no rmal untreated rats. Long-term administration of meloxicam, at two dose lev els, produced significant antioedemetous effect and succeeded in modulating the altered parameters affected during arthritis. The selected dose regime ns of meloxicam did not show any apparent lesions in the gastric mucose. Th e results of the present investigation lend further support to the reported observations concerning selective COX-2 inhibitors. The modulatory influen ce of meloxicam on the oxidant status, particularly on lipid peroxidation a nd thiols might be a relevant effect accounting for its anti-inflammatory p roperties. (C) 1999 Academic Press.