Different cell kinetic changes in rat stomach cancer after treatment with celecoxib or indomethacin： Implications on chemoprevention

AIM: Mechanisms underlying the chemopreventive effects of cyclooxygenase (COX) inhibitors remain elusive. We have previously shown that celecoxib but not indomethacin could prevent carcinogen-induced gastric cancer development in Wistar rats. This chemopreventive effect appeared to be independent of COX-2 and prostaglandin (PG) E2 suppressionsince the lowest PGE2 was obtained in indomethacin group.This study compared the cell kinetic changes in stomachs of rats after treatment with celecoxib (5, 10, 20 mg/(kg.d)) or indomethacin (3 mg/(kg.d)) to gain more insights into the chemopreventive mechanism. METHODS: The apoptosis and proliferation indexes in gastric tumor, adjacent non-cancer tissues and normal gastric tissues were determined. Apoptosis was quantified by apoptotic nuclei counting and TUNEL, whereas proliferation was determined by Ki67 immunostaining. RESULTS: Treatment with either celecoxib or indomethacin inhibited gastric tumor proliferation by more than 65%(P