The effects of indomethacin on A/J mice were investigated. The non-steroida
l antiinflammatory drug (NSAID) indomethacin reduced significantly the numb
er 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 immunocytoch
emistry, COX-2 immunoreactivity was present in the cytosol of lung adenomas
, and in epithelial cells lining the bronchioli and bronchus as well as typ
e 2 alveolar cells. COX-1 immunostaining was similar to that of COX-2 in th
e lungs of urethane-injected mice treated with or without indomethacin. By
RT-PCR, COX-1 and COX-2 PCR products were present in mouse hung adenomas; a
lveoli and bronchioli. These results suggest that indomethacin may inhibit
COX-1 and COX-2 in the A/J mouse lung resulting in reduced adenoma formatio
n.