RESUMEN
<p><b>OBJECTIVE</b>To observe the changes in gene expression of cyclooxygenase (COX) during spontaneous recovery from stress ulcer in rats exposed to water immersion and restraint stress (WRS).</p><p><b>METHODS</b>A rat model of stress ulcer was established by means of WRS, in which the changes in COX expression were detected with immunohistochemistry and reverse transcription (RT)-PCR.</p><p><b>RESULTS</b>Very low levels of COX-2 expression were detected in the gastric mucosa of the control rats, and the expression increased significantly during the healing process of the stress ulcer (P<0.05). COX-1 expression in the gastric mucosa showed no significant difference between the control group and the stress ulcer groups during healing (P>0.05).</p><p><b>CONCLUSION</b>COX-1 and COX-2 expressions in rat gastric mucosa during the recovery from stress ulcer participate in the recovery of the damaged mucosa possibly by mediating prostaglandin secretion.</p>