ABSTRACT
<p><b>OBJECTIVE</b>To investigate the effects of diabetes mellitus on amplitude of distortion product otoacoustic emissions ( DPOAE) and whether streptozotocin has ototoxicity or not.</p><p><b>METHODS</b>Twenty-four SD rats were divided into diabetes mellitus group, insulin therapy group and control group. Diabetes was induced by streptozotocin. The blood glucose of insulin group was controlled by insulin. The amplitude of DPOAE was tested before streptozotocin injection and 3 months, 5 months after injection, respectively.</p><p><b>RESULTS</b>The amplitude of DPOAE in diabetes rats was decreased in 3 months and there was statistical significance (P <0. 05) in 1038, 4126 and 5200 Hz, while obviously reduced in 5 months in all frequencies and there was also statistical significance (P <0. 01). The amplitude of DPOAE in all frequencies lacked of any significance between insulin therapy group and control group.</p><p><b>CONCLUSIONS</b>Diabetes mellitus could induce the amplitude of DPOAE decreasing. Streptozotocin had not evident toxicity for inner ear.</p>