[The beneficial effect of selenium against induction of squamous cell carcinoma of the tongue in rabbits].

Objectives: In a rabbit model of squamous cell carcinoma of the tongue, we monitored histopathologic changes and assessed the effect of selenium against carcinogenesis.

Study Design: The study included 36 male albino New Zealand rabbits. To induce squamous cell carcinoma of the tongue, 9,10-dimethyl-1,2-benzanthracene (DMBA)-acetone solution was applied three times a week for a duration of 20 weeks under anesthesia with xylazine hydrochloride and ketamine. The rabbits were randomly assigned to receive either pure tap water (24 rabbits) or tap water supplemented with 4 ppm sodium selenite (12 rabbits). One rabbit in each group was sacrificed at the end of 4, 8, 12 and 16 weeks, and the remaining rabbits at the end of 20 weeks for macroscopic and microscopic examination of the tongue.

Results: By week 20, two rabbits in the selenium group, and nine rabbits receiving tap water died from acute necrotizing bronchopneumonia due to pasteurellosis. Dysplasia was significantly less in selenium-receiving rabbits (16.7% vs 66.7%, p < 0.0001), and its development manifested a delayed onset. Carcinoma in situ was detected in 25% of tap water-receiving rabbits that remained alive by week 19 to 20, while none of the rabbits had carcinoma in situ in the selenium group.

Conclusion: Our data demonstrate that selenium has an inhibitory and preventive effect against chemically-induced rabbit tongue carcinogenesis.