Controversial Role of Folic Acid on Diabetic Auditory Neuropathy

Abstract

Objective: Diabetic auditory neuropathy (DAN) is a common complication of diabetes that seriously affects the quality of life in patients. In this study, we investigate the role of folic acid in the treatment of DAN in an experimental rat model. Methods: Thirty-two Sprague–Dawley rats were equally divided into four groups: group 1, normal; group 2, diabetic rats; and groups 3 and 4, diabetic rats treated with folic acid (40 and 80 mg/kg, respectively). We used some tools to investigate the therapeutic effect of folic acid on DAN. We evaluated auditory brain stem response (ABR), estimated the volume and number of spiral ganglion and the volume of stria vascularis and spiral ligament by the stereological method, and measured the blood levels of homocysteine (HCY), malondialdehyde (MDA), and superoxide dismutase (SOD). Results: Our study showed that folic acid treatment was not significantly effective in improving structural and functional disorders in DAN, even though its effectiveness in reducing HCY (P < 0.001) and MDA (P < 0.05) as oxidative biomarkers was significant. Conclusion: Folic acid is not effective in relieving morphological and functional disorders in DAN.