The Effects of Sodium Salicylate on the Cochlea of Young Rats;A Structural Study

Abstract

The ototoxicity of salicylate has been known and studied for many years. However, there are many discrepancies about the site and mechanism of ototoxic effects of salicylate on the cochlear structure. In order to investigate the ultrastructural changes of the cochlea, high doses of sodium salicylate (500-600 mg/Kg, once a day for 5-7 days) were injected subcutaneously to Sprague-Dawley rats weighing 80-120 gm. The organ of Corti and the stria vascularis were examined under scanning and transmission electron microscopes. Extensive vacuolization which forms characteristic blisters of the cell surface was observed in the outer hir cells. Both in the outer and inner hair cells disarrangement of the stereocilia was seen. It appeared that the apical portions of the cochlea showed more severe changes of stereocilia than basal portions. The stria vascularis did not reveal any distinctive changes. It was concluded that the ototoxicity of salicylate caused the ultrastrutural changes of hair cells in the organ of Corti of rat cochlea and that outer hair cells were more susceptible than the inner hair cells.