LEVELS OF CYCLOOXYGENASE-1 AND CYCLOOXYGENASE-2 MESSENGER-RNA EXPRESSION AT VARIOUS STAGES OF ACUTE GASTRIC INJURY-INDUCED BY ISCHEMIA-REPERFUSION IN RATS

Recently, the state of cyclooxygenase (COX) mRNA expression has been r eported in an acetic acid-induced chronic gastric ulcer model of mice, However, the time course of COX expression during the developmental s tage and the subsequent repair process of acute gastric injury is not well understood at present. In this study, we quantitatively investiga ted the time course of the level of COX-2 and -1 mRNA expression from the developmental stage through the healing stage in ischemia-repel fu sion (I-R)-induced acute gastric damage. COX-2 mRNA was expressed at l ow or undetectable levels in the normal gastric tissues of control rat s. The COX-2 expression between 6 and 48 h following I-R was higher th an that of the control gastric tissues; the histological findings were erosion during 1-36 h and transitional appearance from erosion to ulc er at 48 h. The maximum expression of COX-2 mRNA was recorded at 24 h (approximately 200-fold elevation). The COX-2 message was very low or undetectable at 72 h (ulcer stage) and at 96 and 120 h (healing stage of ulcer) after I-R. The level of COX-1 mRNA remained stable through a ll stages of acute gastric damage. These results are potentially usefu l for understanding the role of COX and evaluating the effects of drug s on expression of COX at various stages of acute gastric injury. (C) 1998 Academic Press.