Effects of passive smoke inhalation on the vocal cords of rats.
Few studies have demonstrated the pathologic reactions yielded by smoke inhalation on the airway in rats.


OBJECTIVE
The aim of this study was to analyze the possible histopathological effects produced by chronic cigarette smoke inhalation on the vocal folds of rats.


METHODS
Experimental.


METHODS
36 male rats (Rattus norvergicus Wistar strain), aged 60 days, were kept in cages and exposed to inhalation of the smoke produced by 10 cigarettes lit 3 times a day, 7 days a week, for periods of 25, 50 and 75 days, and their respective controls. Thereafter the animals were killed and their larynxes were dissected and submitted to histological processing for achievement of histological sections, which were stained with Hematoxylin and Eosin and analyzed by light microscopy.


RESULTS
The rats exposed to smoke displayed smaller (p< 0,05) body mass than the control group. There was hyperplasia and squamous metaplasia in the free edge of the vocal fold and squamous hyperplasia on the middle portion of the vocal fold in all 3 study periods. Moreover, the 50-day group revealed keratinizing metaplasia in this area. Morphological alterations in other areas of the larynx and inflammatory reaction of the lamina propria were also not observed.


CONCLUSIONS
It was concluded that the passive inhalation of cigarette smoke yields important morphological changes in the vocal fold epithelium, which may progress to neoplasia.
Duarte
Josilene Luciene
JL
de Faria
Flavio Augusto Cardoso
FA
Ceolin
Danielle Santi
DS
Cestari
Tania Mary
TM
de Assis
Gerson Francisco
GF
D000818:Animals; D007830:Larynx / Q000473:pathology; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors; D014028:Tobacco Smoke Pollution / Q000009:adverse effects*; D014827:Vocal Cords / Q000473:pathology
D014028:Tobacco Smoke Pollution