Outer hair cell loss and alterations in glycogen due to tobramycin sulfate.

A total of 26 albino guinea pigs were treated with 200 mg/kg/day of tobramycin sulfate. Animals were killed at various intervals of up to three weeks after seven days treatment. Outer hair cell (OHC) loss of the organ of Corti was evaluated by surface preparation techniques, and glycogen was assessed with PATCO- and PAS-stained sections. We have concluded that permanent damage of OHCs is most prevalent in areas that normally have the least amount and the smallest granule size of glycogen. With treatment, these susceptible areas are the least responsive in terms of an early increase in glycogen production. Furthermore, by 21 days after seven days of treatment, these same areas will reveal an almost total loss of glycogen at a time when damage is maximal.