Scanning Electron Microscopy of the Tongue, Pharynx, and Larynx of Rats Exposed to Cigarette Smoke

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Objective. To examine, by using scanning electron microscopy, the surface of the tongue, pharynx, and larynx of animals exposed to tobacco.Study Design. Experimental study.Methods. Twenty rats were allocated to two groups: group I, control group: 10 rats not exposed to any inhaling pollutant and group II, tobacco group: 10 rats exposed to smoke from 10 cigarettes twice a day for 260 days. Animals of both groups had no restriction of food or water. After those 260 days, their aerodigestive segment was removed, and fragments of their tongue, hypopharynx, and right vocal fold were immersed in 2.5% glutaraldehyde and prepared for scanning electron microscopy.Results. The filiform tongue papillae of the tobacco group were irregularly displayed, flattened, and adhered to each other. The hypopharynx mucosa was highly irregular, thickened, rough and had increased superficial peeling. The mucosa of the vocal folds had deep furrows surrounding the cells. These alterations were not identified for the control group.Conclusion. Several changes were recorded for the tongue, pharynx, and larynx of tobacco group animals, confirming the harmful effects of smoking to the respiratory and digestive epithelium.