Effect of misoprostol and indomethacin on cyclooxygenase induction and eicosanoid production in carrageenan-induced air pouch inflammation in rats

Abstract

Effects of misoprostol, a synthetic prostaglandin E 1 (PGE 1) analogue, on cyclooxygenase-2 (COX-2) protein level and exudate prostaglandin E 2 (PGE 2) and thromboxane B 2 (TXB 2) level were investigated in acute carrageenan-induced air pouch inflammation in rats. Treatment with misoprostol (12.5, 25, and 50 μg/kg) has been started in separated groups, 30 min and 2 days before carrageenan injection and it was given twice a day (total of five doses) by orogastric route. Indomethacin, in doses of 0.5 and 5 mg/kg, and specific COX-2 inhibitor SC-58236, in doses of 5, 10, and 20 mg/kg were given 1 h before carrageenan injection by the orogastric route. Misoprostol increased the levels of PGE 2 and COX-2 protein at all doses applied. Despite indomethacin and SC-58236 increased the level of COX-2 protein when they used alone, these drugs partially inhibited misoprostol-induced increase in the level of COX-2 protein. Partial inhibition of misoprostol-induced increase in the level of COX-2 protein by indomethacin or SC-58236 may indicate the modulatory roles of endogenous prostaglandins (PGs, especially, PGE 2) on the COX-2 expression.