Ibuprofen suppresses depressive like behavior induced by BCG inoculation in mice: role of nitric oxide and prostaglandin.

Prostaglandins (PGs) and nitric oxide (NO) may be involved in the pathophysiology of depression. Since NSAIDs decrease PGs and NO production, they may have an antidepressant effect. The aim of the present work was to explore a possible antidepressant action of ibuprofen in the new model of Bacillus Calmette-Guerin (BCG) induced depression. Mice injected with BCG (10(7) CFU/mouse intraperitoneally) showed an increase in the total immobility time during the forced swim test (FST) and the tail suspension test (TST) and an increase in cerebral PGE2 and NO levels. Fluoxetine administered in drinking water at a dose of 80 mg/l, 5 days before BCG and for 2 more weeks resulted in significant decrease in total immobility time during FST and TST and in cerebral PGE2 and NO levels. Both ibuprofen (200 mg/l) and L-NAME (1 g/l) administered in drinking water 24 h before BCG and for 2 more weeks resulted in decrease in the total immobility time during FST and TST and in cerebral PGE2 and NO levels, which was comparable to fluoxetine's effect. On the other hand, l-arginine administered at a dose of 6 g/l in drinking water together with ibuprofen or fluoxetine reversed their effect on FST, TST and cerebral PGE2 and NO levels. Immunohistochemistry showed a decrease in COX-1 and i-NOS immunoreactivity in the CA1 and CA3 areas of the hippocampus following ibuprofen treatment. These results suggest that ibuprofen may have an antidepressant effect through inhibition of PGE2 and NO production, especially in depression secondary to chronic inflammation.