Objective: The purpose of this study was to investigate the effects of environmental tobacco smoke (ETS) and house dust mite allergen (HDMA) on the laryngeal mucosa of guinea pigs.
Study design: Prospective, controlled animal study.
Subjects and methods: Sixteen juvenile guinea pigs were randomly assigned to one of four treatment groups: (1) filtered air, (2) HDMA, (3) ETS, and (4) ETS and HDMA. The mucosal response of retrieved larynges was measured by eosinophil grade and stored mucin index.
Results: HDMA exposure increased eosinophil grade in the supraglottis. The mean eosinophil grade in the supraglottis was 1.25 (+/-1.26) in the filtered air group. The grade increased to 3.60 (+/-0.89) in the HDMA group (P = 0.021) and 3.00 (+/-1.16) in the ETS/HDMA group (P = 0.078). HDMA and ETS exposure was associated with increased mucin index in the subglottis. The grade increased from 1.50 (+/-1.73) in the control group to 3.25 (+/-0.50) in the ETS, 2.80 (+/-1.64) in the HDMA, and 3.25 (+/-0.50) in the ETS/HDMA group (P < 0.05).
Conclusion: Exposure to HDMA was associated with eosinophilia in the supraglottis. Exposure to HDMA and ETS was associated with elevated mucin in the subglottis. These results provide further evidence that ETS and inhaled allergens may play a role in the development of chronic laryngitis.