An immunohistochemical method for the study of aminoglycoside ototoxicity in the guinea pig cochlea using decalcified frozen sections.

An immunohistochemical technique with decalcified frozen sections was used to study aminoglycoside ototoxicity. Decalcified guinea pig cochleas were cut with a fine blade parallel to the plane of the modiolus to facilitate the penetration of inclusion material and the manipulation of frozen sections. Light microscopy was carried out and additional frozen sections were employed for an immuno-electron microscopic study. Twenty-four hours after a single transtympanic injection of 10 mg gentamicin, there was a definite distribution of the drug in only type I hair cells of the ampullae as well as in both inner and outer hair cells along the length of the cochlea. In those animals treated intraperitoneally with 200 mg/kg amikacin for 8 days, the drug was located in the outer hair cells of the cochlea, with a tendency to decrease from base to apex and in the inner hair cells towards the apex.