Lipoic acid rescues DBA mice from early-onset age-related hearing impairment.

We fed DBA mice with alpha-lipoic acid (100 mg/kg body weight/day), beginning 2, 4, or 8 weeks after birth. Hearing thresholds were measured weekly. At 12 weeks after birth, control mice not fed with alpha-lipoic acid showed significant hearing decreases at all frequencies. In contrast, mice fed with alpha-lipoic acid beginning at 2 weeks after birth showed significantly better hearing at all frequencies. Mice fed with alpha-lipoic acid beginning at 4 and 8 weeks after birth also showed significantly better hearing than control mice after they were fed with alpha-lipoic acid. The stria vascularis of mice fed with alpha-lipoic acid showed reduced 8-oxoguanine residues in DNA and cytoplasm compared with that of control mice. Western blotting showed that the level of hypoxia-inducible factor-1alpha was lower in mice fed with alpha-lipoic acid than in control mice. From these results, we suggest that alpha-lipoic acid prevented early-onset hearing impairment in DBA mice.