Nitric Oxide Expression In Oral Mucosa Hyperkeratosis Vs. Leukoplakia

OBJECTIVE: The aim of this study was to determine and compare the (NO) Nitric Oxide expression in oral mucosa hyperkeratosis and in oral leukoplakia lesions. METHODS: Forty-two (42) patients (22 male and 20 female), aged 30-65 years were included in this study after informed consent. Nine (9) of these were afflicted with oral hyperkeratosis, twenty-one (21) patients presented oral homogeneous leukoplakia, twelve (12) suffering from oral nodular leukoplakia. Five (5) healthy patients to be treated for impacted third molar extraction were also included in the study as control group. Immunohystochemical, RT-PCR and Western Blot analysis were used to localize Nitric Oxide in the examined samples. RESULTS: Our results showed that inducible nitric oxide synthase (iNOS) activity was higher in hyperkeratosis and in leukoplakia when compared to healthy mucosa. iNOS was not expressed in healty oral mucosa. It was also found a gradual increase of neuronal nitric oxide synthase (nNOS) activity together with the progression of the lesions. CONCLUSIONS: These results could ascribe to nitric oxide a determinant role in growth and development of hyperkeratosis and leukoplakia, so we hypothesize the use of NO as a marker in the precocious diagnosis of precancerous oral lesions.