Investigation of the ototoxic effects of interferon alpha 2A on the mouse cochlea

This prospective randomized study investigates the possible toxic effects o f interferon (IFN) (alpha 2A on the mouse cochlea. Thirty-six albino Swiss mice that were randomly assigned to 3 groups underwent baseline auditory br ain stem response testing bilaterally to objectively assess baseline hearin g levels. The first group received a single dose of 50,000 units, and the s econd group received 100,000 units of IFN-alpha 2A intraperitoneally, where as the third group was given no medication. Repeat auditory brain stem resp onse testing revealed a significant rise in mean baseline peak equivalent s ound pressure level thresholds in the groups that received IFN (P < 0.001), Histologicallly, the cochleae of mice that received IFN had a decreased nu mber of fibroblasts in the spiral limbus, as well as prominent cytoplasmic vacuolation of these cells, compared with control animals. Loss of hair cel ls was not observed. It is possible that reversible biochemical and metabol ic changes in the cochlea, rather than morphologic abnormalities, manifest IFN ototoxicity.