Changes in Eustachian Tube Mucosa in Mice After Short-Term Tobacco and E-cigarette Smoke Exposure

Objectives: To evaluate histologic changes in middle ear and eustachian tube (ET) mucosa of mice after exposure to tobacco or electronic cigarette (e-cigarette) smoke. To determine whether there were any mitigating effects of middle ear application of anti-IL-13 or the epidermal growth factor receptor antagonist AG1478 on noted changes within ET mucosa.

Study design: Controlled animal study.

Methods: Fifty BALB/cJ mice were randomly assigned to one of five groups: A control group with no smoke exposure, two groups exposed to tobacco smoke, and two groups exposed to e-cigarette vapor. Within the exposed groups after 4 weeks of exposure, one ear was infiltrated with a saline hydrogel and the other ear with hydrogel of either Anti-IL-13 or AG1478. After four more weeks of exposure, the animals were euthanized and the ETs were evaluated for mucosal changes.

Results: Compared to control animals with no smoke exposure, there were significant decreases in the numbers of goblet cells within the ET mucosa of mice exposed to tobacco smoke and e-cigarette vapor. No significant differences in cilia, mucin, or squamous metaplasia were noted. Neither anti-IL-13 nor AG178 significantly altered goblet cell count in the ET mucosa of mice exposed to tobacco smoke; however, both agents significantly increased goblet cells within the ET mucosa of mice exposed to e-cigarette vapor.

Conclusion: Short-term tobacco smoke and e-cigarette vapor significantly decrease goblet cell count in mouse ET mucosa. Middle ear application of both anti-IL-13 and AG1478 resulted in an increase in goblet cell count among mice exposed to e-cigarette vapor, but not to tobacco smoke.

Level of evidence: NA Laryngoscope, 132:648-654, 2022.