[The effect of nonsteroidal anti-inflammatory drugs on oxidative/antioxidative balance]

Arachidonic acid cascade activated by cyclooxygenase is an important source of reactive oxygen species. Nonsteroidal anti-inflammatory drugs (NSAIDs) can shift an oxidative-antioxidative balance towards antioxidation by inhibiting cyclooxygenase. The aim of the study was to assess the influence of nonsteroidal antiinflammatory drugs on the oxidative-antioxidative balance using animal model.

. In the study acetylsalicylic acid (ASA) as COX-1 and COX-2 inhibitors, and nimesulide as selective COX-2 inhibitor were used. An investigation was carried out on rats (of both sex), divided into two groups of ten animals each. Rats were given intragastrically for three weeks: acetylsalicylic acid (ASA) at doses of 2 and 10 mg/kg bw/day diclofenac at doses of 1 and 5 mg/kg bw/day, and nimesulide at doses of 2.5 mg and 12.5 mg/kg bw/day. Control group received water. Total antioxidant capacity, nitrotyrosine and TBARS in plasma, sulfhydryl groups in whole blood, and thiobarbiturate (TBARS) in hemolysates of erythrocytes concentrations were assessed.

The applied doses of diclofenac significantly increased TBARS and nitrotyrosine concentrations and decreased total antioxidant capacity whereas ASA quite the opposite: decreased TBARS and nitrotyrosine concentrations and increased total antioxidant capacity. Nimesulide only at the dose of 12.5 mg/kg bw/day caused a decrease in plasma TBARS and nitrotyrosine concentration.

This study demonstrated the potential antioxidant properties of ASA and nimesulide but not the other non-selective NSAIDs--diclofenac which turned out to exert pro-oxidative effects. ASA appears to possess stronger antioxidant activity than nimesulide.