Dynamic Rabbit Model of Ear Barotrauma

BACKGROUND: Establishing animal models of ear barotrauma (EB) to provide evaluation criteria for Eustachian tube dysfunction.METHODS: Using expansive sponges, 70 rabbits' right pharyngeal openings of the auditory tubes were blocked to cause dysfunction in the right Eustachian tubes. The right tympanic cavities of 65 rabbits were the Model Group (Subgroups 1-13) and these rabbits' left tympanic cavities were the Nonblockage Group. Hypobaric chamber tests (HCTs) at various vertical speeds (100 m · s^-1, 75 m · s^-1, 50 m · s^-1, and 15 m · s^-1) and altitudes (13,123 ft and 6562 ft) were conducted. The remaining five rabbits' right tympanic cavities were the Control Group and no HCTs were conducted. After HCTs, observations were made on rabbits' behavioral changes, oto-endoscope and tympanometry results, and pathological changes of the tympanic mucosae.RESULTS: 1) Rabbits in Subgroups 1-12 demonstrated EB, while Subgroup 13 and the Control Group did not. 2) Histopathology showed EB caused by rapid ascent/descent at 100 m · s^-1 was more severe than that of 75 m · s^-1 and 50 m · s^-1 (P < 0.01), and that there were no significant differences in EB caused by rapid ascent/descent at 75 m · s^-1 and 50 m · s^-1 (P > 0.05). There were no significant differences in pathological injuries at the altitudes of 6562 ft and 13,123 ft (P > 0.05). 3) Based on tympanic membrane structures, tympanometry, and histopathological results, rabbits' EB can be classified into mild, moderate, and severe.DISCUSSION: EB's dynamic models could be established through HCTs on rabbits with Eustachian tube dysfunction.Wang B, Xu X, Lin J, Jin Z.