Effects of the anti‐inflammatory agents indomethacin, metiamide and acetylsalicylic acid on the induction of hyperplasia in hamster cheek‐pouch epithelium and ear epidermis

Previous studies have shown that agents such as indomethacin and hydrocortisone act to reduce the level of epidermal hyperplasia produced by various chemicals, but little information is available about the effects of such anti‐inflammatory agents on the induction of hyperplasia in oral mucosa. Hamster cheek‐pouch epithelium and ear epidermis were treated with indomethacin, metiamide and acetylsalicylic acid prior to treatment with turpentine, podophyllin or TPA. The levels of hyperplasia induced were monitored by rates of epithelial glycolysis, protein synthesis and mitosis. The response of the metabolic assays to epinephrine was also examined. Alone, turpentine, podophyllin and TPA each caused a 3–5 fold increase in the metabolic assays and loss of the normal tissue response to epinephrine. Tissues pretreated with indomethacin showed significant reductions in the levels of hyperplasia produced and they retained a normal response to epinephrine. No reduction in hyperplasia was observed following pretreatment with acetylsalicylic acid, an alternative inhibitor of prostaglandin synthesis or with metiamide, a histamine blocker. The results indicate that the production of epithelial hyperplasia by turpentine, podophyllin and TPA can be inhibited by indomethacin.