Ototoxicity of Capreomycin

Abstract

The present authors injected capreomycin (CPM) 400mg/kg intramuscularly into 10 albino guinea pigs of the Hartley strain (about 300g at the start of the experiment) for 28 days and simultaneously kanamycin (KM) 400mg/kg into 11 guinea pigs of the same strain for the same period. Preyer pinna reflex test was performed before, during and after the injection of the antibiotics with audiometer for the guinea pig. All of these animals underwent intravital fixation with Wittmaack's fixative through the ascending aorta under nembutal anesthesia. Bilateral temporal bones were taken enbloc from the skull and fixed further in the same fixative for several days. These temporal bones were decalcified, rinsed under running water, dehydrated and then embedded in celloidin. The serial horizontal celloidin sections including the both cochlea (25-30 microns in thickness) were stained with hematoxylin-eosin.Histologic changes of the internal ear, especially, damages of the organ of Corti and stria vascularis were examined.1) CPM caused the disappearance of the outer hair cells of the organ of Corti localized in the lower part of the hook (lower 1/4 of the 1 turn) of the cochlea in 40% of the 10 CPM injected guinea pigs.2) KM induced relatively extensive loss of the outer hair cells extending from the lower end of the basal turn to the upper turn of the cochlea in 100% of the 11KM treated guinea pigs.3) The present experimental study indicated that CPM is less ototoxic in guinea pigs than KM.4) There was no distinct morphological evidence of vestibular damage in the guinea pigs.