EXPRESSION OF THE CYCLOOXYGENASE-2 GENE IN GASTRIC EPITHELIUM

This study examined the mRNA level of cyclooxygenase-2 (cox-2) in a ra t gastric mucosal cell line after growth stimulation in vitro and in r at gastric mucosa before and after acid-induced injury in vivo. RGMI c ells were stimulated with fetal calf serum in the in vitro study. Ther eafter, the cox-2 mRNA level was examined by Northern analysis. Effect s of NS-398, a specific inhibitor of cox-2, and indomethacin on prosta glandin production and cell proliferation were examined in RGM1 cells. In the in vivo study, rats were given 1 mi of 0.6 N hydrochloric acid into the stomach. The level of cox-2 mRNA was examined in rat gastric mucosa after acid administration. Cox-2 mRNA increased 20-60 min afte r growth stimulation in RGM1 cells. Both NS-398 and indomethacin suppr essed prostaglandin production and cell proliferation after growth sti mulation. Expression of cox-2 mRNA was observed 40 and 60 min after ad ministration of 0.6 N HCl. Gastric lesions developed within 60 min aft er HCl administration and healed significantly within 48 h. The presen t study shows the expression of cox-2 in gastric epithelial cells in v itro and in gastric mucosa after injury in vivo. The results also sugg est that cox-2 is involved in de novo synthesis of prostaglandins and cell proliferation in gastric epithelium.