Gentamicin affects connexin 26 expression in the cochlear lateral wall

Aminoglycosides may decrease the expression of some proteins participating in ion-exchange in the cochlear lateral wall. Connexin 26 expression in the lateral wall may play a role in acquired hearing loss by maintaining the endocochlear potential and potassium concentration in the endolymph. We examined the effects of gentamicin on the expression of connexin 26 to obtain a better understanding of aminoglycoside ototoxicity. We detected changes in connexin 26 protein and mRNA expression in the cochlear lateral wall using immunohistochemistry staining, western blotting, and real-time PCR in rats after administration of a single dose of gentamicin. The expression of connexin 26 increased over time in type III fibrocytes after gentamicin administration. Elevated protein levels were detected 3 h after the single injection of gentamicin; while, mRNA levels increased after 24 h. Connexin 26 plays an important role in the acute effects of high-dose gentamicin and is probably involved in the pathogenesis of ototoxic deafness.