Pathophysiology of the Ototoxicity of Cis‐Diamminedichloroplatinum

TLDR

The study examined electrophysiologic and histopathologic changes in the guinea pig inner ear following cis‑diamminedichloroplatinum administration. Cis‑platin caused a progressive loss of endocochlear potential and cochlear microphonics, with a transient large negative summating potential, while histology revealed basal‑turn outer hair cell loss, preserved inner hair cells, slight stria vascularis atrophy, and severe collapse of Reissner’s membrane.

Abstract

The electrophysiologic and histopathologic changes in the inner ear caused by the administration of cis-diamminedichloroplatinum (CP) were studied in guinea pigs. The endocochlear dc potential (EP) gradually decreased after the intravenous injection of CP and reached approximately 0 mV on the fourth day, but the EP did not become negative. The cochlear microphonics also diminished and could not be recorded on the fourth day. The negative potential of the organ of Corti remained in the normal range during the experiment. A large negative summating potential (SP) was observed one day after injection, but the amplitude of the negative SP became small on the second day. Light microscopic examination demonstrated that the outer hair cells are destroyed in the basal turn of the cochlea and are preserved in the upper turns, while the inner hair cells are almost completely preserved in all turns. The stria vascularis was found to be slightly atrophic. Severe collapse of Reissner's membrane was observed in the basal turn.