Cyclooxygenase-2 in models of acute lung inflammation : expression of the enzyme and the effect of selective inhibition

Prostanoids are important mediators of inflammation and tissue homeostasis. Cyclooxygenase (COX) is a key enzyme in the biosynthesis of prostanoids from arachidonic acid. Of the two isoforms of COX, COX-1 functions in tissue homeostasis whereas COX-2 is more abundant in inflammation. Selective COX-2 inhibition seems effective in reducing inflammation with fewer side effects compared with non-selective COX inhibitors. In this study, the expression of COX-2 in lung inflammation was investigated in two models, which include acute rejection and antigen-induced inflammation. The effect of selective COX-2 inhibition in these models was also determined. COX-2 was expressed in infiltrating cells in both models, in addition to constitutive expression in bronchial epithelium and bronchial smooth muscle cells. Selective COX-2 inhibition significantly reduced the extent of inflammation in both models. These results suggest that selective COX-2 inhibition may be effective in the treatment of acute rejection and asthma