Effects of anti-inflammatory drugs upon nitrate and myeloperoxidase levels in the mouse pleurisy induced by carrageenan.

The effects of several drugs (terfenadine, bradykinin B2 receptor antagonists: HOE 140, NPC 17731, diacerein, indomethacin, meloxicam, nabumetone, and dexamethasone) upon myeloperoxidase and nitrate levels were analyzed in an inflammation model characterized by biphasic peaks (4 and 48 h) of cell migration and of fluid leakage. Myeloperoxidase levels were significantly higher only in the first phase (4 h; median and range; 537.5; 323.6-683.7 mU/ml; P < 0.01), whereas increased mean nitrate levels were detected in both phases (4 h: 19.0; 6.2-32 microM and 48 h: 13.7; 8.9-17.8 microM; P < 0.01). Enhancement of both cell migration and myeloperoxidase levels, 4 h after pleurisy induction, was effectively inhibited by all studied drugs. All of them, except diacerein also inhibited exudation. At this time, nabumetone and diacerein also significantly reduced nitrate levels (P < 0.01). Regarding the second phase (48 h), although dexamethasone, diacerein, and terfenadine decreased either cell migration or exudation, no drugs caused any change in the levels of nitrate. These results indicate that the degree of inhibition of the tested drugs upon the parameters studied do not match, suggesting that differences in these effects may certainly interfere with their efficacy.