(A) ABR hearing thresholds were measured at 32, 16, and 8 kHz from control diet and/or calorie restricted WT (left) and Sirt3−/− (right) mice at 2 and 12 months of age (n = 9–12). *Significantly different from 2-month-old WT or Sirt3−/− mice (P < 0.05), **significantly different from 12-month-old WT mice (P < 0.05). CD = control diet, CR = calorie restricted diet.
(B–M) Neurons in the basal cochlear regions from WT mice in control diet at 2 (B and C) and 12 (F and G) months of age, and calorie restricted diet at 12 months of age (J and K). Neurons from control diet Sirt3−/− mice at 2 (D and E) and 12 (H and I) months of age, and calorie restricted Sirt3−/− mice at 12 months of age (L and M)(n = 5). Arrows in the lower magnification photos indicate neuron regions. Scale bar = 100 µm (B, F, J, D, H, and L), 20 µm (C, G, J, E, I, and M). Data are means ± SEM. See also Figure S1, Figure S2, and Figure S3.