Evaluation of the Effect of Two Different Systemic Doses of Viola Odorata on Prevention of Induced Tongue Dysplasia in Rats

STATEMENT OF THE PROBLEM Oral cancer is among the ten most common cancers worldwide. It affects the life quality of patients in many ways. PURPOSE The aim of this study was to compare the effects of two different systemic doses of Viola Odorata syrup on the prevention of 4-Nitroquinoline-1-oxide (4-NQO) induced tongue dysplasia in rats. MATERIALS AND METHOD Forty-eight male Wistar rats were divided into four groups of A, B, C and D. Group A served as the control group. The rats in groups B to D received 30 ppm of 4-NQO in drinking water for 12 weeks. Additionally, the rats in groups B and C received Viola Odorata syrup at doses of 15 and 5 ml/kg, respectively, 3 times a week. Body weights were measured three times a week. At the end, the rats were euthanized and the tongue was removed. Histological evaluations for carcinogenesis were carried out under a light microscope. RESULTS The mean body weight of the rats in groups B, C, and D were lower than that in group A (p< 0.01). After 12 weeks of treatment, microscopically no histological changes of the tongue base epithelia were observed in the control group. The rats in group B did not show severe dysplastic changes; only mild to moderate histological changes including hyperplasia and hyperkeratosis were evident. These incidences were significantly more apparent in groups C with moderate to severe changes (p< 0.05) and group D with severe dysplastic changes (p< 0.01). Almost all rats in group D had hyperplasia and manifested all of the stages of dysplasia. CONCLUSION Viola Odorata extract has dose-dependent inhibitory effects on the development of tongue induced dysplasia.