[Effect of sodium thiosulfate on cisplatin-induced ototoxicity]

The effect of sodium thiosulfate (STS) on cisplatin (CDDP)-induced ototoxicity in the guinea pigs was studied by surface preparation, outer hair cell counting, electrocochleographic, light and electron microscopic techniques. Seventy-eight guinea pigs were divided into five groups. Group I received intraperitoneal CDDP (2.5 mg/kg/day) alone: group V as control; the other three groups were given the same doses of CDDP as group I with intramuscular STS (600 mg/kg/day) administered 30 min before (group II) or 30 min (group III) and 6 hr (group IV) after CDDP. The results showed that CDDP produced serious ototoxicity both functionally and histologically when given without STS. The first row of outer hair cells (OHC) in basal turn was first damaged. The inner hair cells (IHC) were more resistant than the OHC. The pattern of destruction is similar to that produced by aminoglycosides. Concomitant use of STS, however, significantly reduced CDDP-induced ototoxicity. Transmission electron microscopy showed the degeneration of mitochondria to be the major and earliest sign of OHC damage induced by CDDP. Our present study documented the good protective efficacy of STS against CDDP cochleotoxicity. STS did not reverse the pathological changes already caused by CDDP. This study provided some experimental evidence for the prevention of CDDP ototoxicity in clinical cancer chemotherapy.