A histopathological study of the inner ear after the administration of hyaluronan into the middle ear of the guinea pig.

Hyaluronan, 19 mg/ml, was administered into the middle ear cavity of guinea pigs. A control group was subjected to a sham operation. Fourteen days after administration the animals were killed and a macroscopic examination of all middle ears was performed. Surface preparations of the organ of Corti were made and examined by light microscopy. Hair cell loss along the length of the sensory epithelium was quantified. No toxic effect of hyaluronan could be detected either in the middle ear or in the sensory cells in the cochlea. Thus hyaluronan is potentially useful for facilitating middle ear surgery.