Functional and pathohistologic changes in an ischemic model of rat inner ear

Abstract

We investigated functional and histopathological changes in the inner ear circulatory disorder caused by thrombosis of the anterior inferior cerebellar artery (AICA) in rats. The thrombosis was induced by a photochemical reaction between green light and systemic injection of Rose Bengal. During this experiment, auditory brainstem responses (ABR) were recorded and cochlear blood flow (CBF) was measured by a laser doppler flowmeter. Within 5 weeks after the procedure, histopathological changes were studied by light microscopy following the observation of equilibrium dysfunction and ABR recording. CBF was reduced from the baseline in 30.8±3.4% (mean±SE, n=25) by occlusion of the AICA, ABR was altered in 96% of animals, and equilibrium dysfunction was observed in 77%. When the AICA was not reopened within a short time, severe histopathological changes were frequently observed. There was no significant correlation between equilibrium dysfunction and histopathological changes in the vestibule. It is concluded that this experimental model may be useful for investigating functional and histopathological changes in the ischemic inner ear. © 1993, The Oto-Rhino-Laryngological Society of Japan, Inc. All rights reserved.