RESUMO
Objective To examine the chemo-preventive effect of cyclooxygenase-2(COX-2) inhibitor (celecoxib) in an animal model of stomach carcinogenesis. Methods Eighty-six male Wistar rats were divided into six groups. The rats were given water alone (group A, n=5), N-methyl-N′-nitro-N-nitrosoguanidine (MNNG) (group B, n=16), 3 mg/kg of indomethacin daily (group C, n=16), 5 mg/kg of celecoxib daily (group D, n=17), 10 mg/kg of celecoxib daily (group E, n=16) or 20 mg/kg of celecoxib daily (group F, n=16). The animals in group B to F were given 10% sodium chloride (in the initial 6 weeks) and drinking water containing MNNG (100 ?g/ml) to induce gastric adenocacinoma. All animals received treatment for 40 weeks, and were sacrificed after death or at week 48. Gastric tumor was evaluated histologically. Results Among 86 rats, 26 rats died, and 60 rats completed the experiment. The incidences of gastric cancer were found 0 (0%) in group A, 12 (75.0%) in group B, 11 (68.8%) in group C, 12 (70.6%) in group D, 3(18.8%) in group E, and 5(31.3%) in group F. There were significant differences in tumor incidence (P=0.002), multiplicity (P=0.001) and volume (P=0.009) among different groups. When compared with group B, the group E had the greatest reduction in tumor incidence (P=0.004), tumor multiplicity ( P=0.006) and mean tumor volume (P=0.02). Treatment with indomethacin had no significant effect on tumor development. Conclusion While treatment with indomethacin had no significant effect on tumor development, treatment with celecoxib reduced gastric cancer incidence and growth in rats.