OTOTOXICITY OF TUBERACTINOMYCIN IN THE GUINEA PIGS

Especially on the Threshold Shift of the Pinna Reflex and Histopathological as well as Histochemical Findings of the Inner Ear

Abstract

The ototoxicity of tuberactinomycin (TUM) was examined by using the audiometer for the guinea pig and histopathologically as well as histochemically on 148 guinea pigs (300g) and compared with the ototoxicity of kanamycin (KM) as well as viomycin (VM). These antibiotics were injected at the various daily doses ; 80mg/kg subcutaneously for 35 days, 100mg/kg, 200mg/kg and 400mg/kg intramuscularly for 28 days, respectively. The incidence of hearing impairment and histological damage was the highest at the daily dose of 400mg/kg; severe hearing impairment associated with extensive loss of the outer hair cells did not occur in the 25 TUM treated animals, but in 4 of the 10 KM treated animals and in 100% of the 10 VM treated ones. No remarkable decrease in succinic dehydrogenase activity of the hair cells of the organ of Corti was found in the TUM treated animals. There was no distinct impairment in equilibrium in the TUM treated animals. It may be concluded that TUM has a mild ototoxicity but its ototoxic effect is much weaker than VM and KM.