Differences in the cochlear degeneration pattern in the guinea pig as a result of gentamicin and cis-platinum intoxication

Abstract

This study gives the result of a series of studies on inner ears carried out with the help of microdissections and surface preparations. The total degeneration patterns of the cochlea of the guinea pig due to 2 different ototoxic drugs were investigated with this technique. Clear differences between the results of the ototoxic drugs (gentamicin and cis-platinum) in the inner ear were observed. Gentamicin has a typical starting point of degeneration on the basilar membrane. From this degeneration point the loss of hair cells progressed towards the round window (fast) and the apex (slowly). The stria vascularis showed no signs of degeneration due to gentamicin. Reissner''s membrane showed cellular vacuolization of the endolymphathic cells. Cis-platinum (DDP) [cis-diamminedichloro platinum II] showed no degeneration point; the loss of hair cells was found over the complete length of the basilar membrane, with a preference for the basilar turn. The stria vascularis showed severe degenerative changes due to DDP; Reissner''s membrane showed no change. In using the microdissection technique, these differences between the 2 ototoxic drugs were observed.