ABSTRACT Several immune mechanisms may lead to inner ear dysfunction: specific and cross-reacting autoantibodies, deposition of circulating immune complexes from bacterial or viral antibodies, cytotoxic T cells agains specific inner ear targets. Corticosteroids are usually associated with dramatic immediate responses and suggests an autoimmune response as the cause of the hearing loss. Corticosteroids exert a potent suppression of the immune-mediated inflammatory response by inhibition of interleukin-1 (IL-1) system. High systemic doses produced higher inner ear drug levels but intratympanic administration resulted in a significantly higher inner ear drug level compared with systemic administration. The existence of a great number of glucocorticoid receptors in the stria vascularis, spiral ligament and the supporting cells of the organ of Corti suggest their role as immune targets of the inner ear and justify the corticosteroid therapy. However, further investigation and analysis of chemical properties in order to reduce the side effects of GC and to improve the inner ear perfusion of delivery systems are needed.
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