Indomethacin reduces lung adenoma number in A/J mice.

The effects of indomethacin on A/J mice were investigated. The non-steroidal antiinflammatory drug (NSAID) indomethacin reduced significantly the number of lung adenomas 3, 4 or 8 months after urethane injection by 28, 30 and 29% respectively. The density of apoptotic cell bodies increased 2.9-fold in the lung adenomas of A/J mice treated with indomethacin. By immunocytochemistry, COX-2 immunoreactivity was present in the cytosol of lung adenomas, and in epithelial cells lining the bronchioli and bronchus as well as type 2 alveolar cells. COX-1 immunostaining was similar to that of COX-2 in the lungs of urethane-injected mice treated with or without indomethacin. By RT-PCR, COX-1 and COX-2 PCR products were present in mouse lung adenomas, alveoli and bronchioli. These results suggest that indomethacin may inhibit COX-1 and COX-2 in the A/J mouse lung resulting in reduced adenoma formation.