NSAID-induced delay in gastric ulcer healing is not associated with decreased epithelial cell proliferation in rats.

Nonsteriodal antiinflammatory drugs initiate gastric ulceration and delay gastric ulcer healing. This study aimed to investigate the role of epithelial cell proliferation in delayed ulcer healing and to identify the most reproducible technique for measuring cell proliferation. Rats with acetic acid-induced gastric ulcers were treated for two weeks with indomethacin (1 mg/kg), aspirin (200 mg/kg), or vehicle control. Ulcers were assessed by macroscopic measurement of ulcer area, quantitative histological measurement of mucosal regeneration, and 5-bromo-2'-deoxyuridine immunohistochemistry to assess epithelial cell proliferation. Indomethacin and aspirin significantly delayed ulcer healing and inhibited mucosal regeneration. Three techniques for assessing cell proliferation were compared, and a scoring system, designed to take into account the entire tissue, was shown to be the most reproducible technique. Indomethacin significantly enhanced cell proliferation in the fundic area of ulcer and aspirin had no effect on cell proliferation. We conclude that aspirin and indomethacin delay ulcer healing by an inhibition of mucosal regeneration, but they do not inhibit epithelial cell proliferation.