Figure 1.

The effect of aging on auditory brainstem response (ABR) thresholds and mitochondrial DNA (mtDNA) integrity. (A) The hearing thresholds of mice at frequencies of 8 kHz, 16 kHz, and 32 kHz increased with aging (fifteen mice per group). (B) The mtDNA integrity was assessed by measuring the expression level of 10 kb amplicon. The mtDNA integrity in the mouse auditory cortex significantly decreased with aging. The data are shown as mean ± standard error of mean (five mice per group; 1 m, 1 month; 6 m, 6 months; 12 m, 12 months; 18 m, 18 months; SPL, sound pressure level). * p < 0.05, ** p < 0.01.