OBJECTIVE: To determine the effects of repeated pepsin/hydrochloric acid (H
Cl) exposure on the eustachian tube (ET).
STUDY DESIGN AND SETTING: ET function was studied in 22 rats. Group I (cont
rol) rats received transtympanic phosphate buffered saline solution; groups
II (0.5 mg/ml) and III (2.0 mg/ml) received transtympanic pepsin/HCl. Test
solutions were applied on day 0 with ET function evaluated on days 1, 2, 3
, and 7 after exposure. Each 7-day period represents 1 cycle; all groups un
derwent 4 cycles. ET function was evaluated using passive opening and closi
ng pressure, and active clearance of positive and negative pressure tests.
RESULTS. Rats exposed to pepsin/HCl had elevated passive opening pressures
and a decreased ability to clear positive and negative pressure. A temporal
relationship exists.
CONCLUSION. The results suggest middle ear exposure to pepsin/HCl leads to
ET dysfunction in rats, and that this dysfunction is enhanced with repeated
exposures.
SIGNIFICANCE., Gastroesophageal reflux may induce ET dysfunction.