RÉSUMÉ
BACKGROUND AND OBJECTIVES: Retinoids have recently become an interest to clinicians because of their ability to inhibit migration and proliferation of the premalignant squamous cells, while enhancing growth and proliferation of normal cells. Aural cholesteatoma is defined as the state of hyperproliferative keratinocytes in the middle ear cavity. An in vitro investigation was undertaken to determine whether all-trans retinoic acid (t-RA) exhibits an inhibitory effect on cholesteatoma cell proliferation. METHODS: Cholesteatoma tissue was obtained during a middle ear operation, and the explant was cultured on six well-plates in a culture medium of Medium M-154 (Cascade Biologics Inc., USA) for one week. T-RA was then treated with 10M, 10M, 10M, 10M concentrations, respectively. The cholesteatoma explant cultures were observed daily, and topographic maps were constructed weekly to quantify the proliferation area. The explant culture area was estimated by Multiscan. RESULTS: In the absence of t-RA, the cholesteatoma explant culture area reached 401.5mm in four weeks. But with the administration of t-RA, the cultured area decreased proportionally to t-RA concentrations which reduced to 224.0 mm, 94.4 mm respectively in four weeks with 10M, 10M concentration of t-RA (p<0.05). CONCLUSIONS: This investigation showed that t-RA has a significant inhibitory effect on cholesteatoma proliferation. These results suggest that retionoids may have a role in controlling cholesteatoma disease.