RESUMO
<p><b>OBJECTIVE</b>To study the feasibility of chemoprevention of esophageal adenocarcinoma by celecoxib, a selective cyclooxygenase-2(COX-2) inhibitor using a rat model.</p><p><b>METHODS</b>Rats were divided into 3 groups: model group, celecoxib group, and control group. The rat surgical model was established by performing a gastrojejunostomy plus an esophagojejunostomy 5 mm distal to the gastrojejunal anastomosis. Twenty-eight weeks after surgery, all the animals were sacrificed and the pathological changes in the esophagus were examined macroscopically. COX-2 expression was analyzed by immunohistochemistry. Prostaglandin E2(PGE2) level was measured by enzyme-linked immunosorbent assay(ELISA).</p><p><b>RESULTS</b>The incidence of Barrett's esophagus and esophageal adenocarcinoma in the model group was 84% and 57% respectively, significantly higher than those in the control group(P<0.01). The incidence of esophageal adenocarcinoma in the celecoxib-treated group was significantly lower than that in the model group(P<0.01), and no esophageal adenocarcinoma was detected in the control group. COX-2 expression was detected in 100% of reflux esophagitis, Barrett esophagus and esophageal adenocarcinoma, but not found in the normal tissue from the esophagus and the jejunum(P<0.01). The PGE2 level in the esophageal tissue in the model group was significantly higher than that in the control group(P<0.01). Rats in the celecoxib-treated group had significantly lower PGE2 level than that in the model group(P<0.01). The PGE2 levels were significantly higher in rats with cancer than those without cancer(P<0.01).</p><p><b>CONCLUSION</b>Celecoxib successfully prevents the development of esophageal adenocarcinoma in a rat surgical model with mixed reflux of acid and duodenal juice and significantly decreases the risk of Barrett esophagus developing esophageal adenocarcinoma. COX-2 maybe an effective selective target of chemoprevention for esophageal adenocarcinoma.</p>