Fig. 1

Histological characterization changes in aging cochleae and the identification of an age-related hearing loss mouse model. A ABR thresholds were observed in 6 W (n = 12) and 12 M (n = 17) C57BL/6 J mice at 4, 8, 16, 24, 32 kHz and click. B Young adult and old aged C57BL/6 J cochlear representative cross sections stained with H&E showed atrophy of SV with age in all three turns. Section thickness is 5 μm. C The quantified analysis of SV in three turns, which showed the most SV atrophy appear in basal turns. D, E, F The difference in HCs counts of young adult and old mice at same locations was calculated, and dramatic loss of HCs in cochlear basal turn was observed. (n = 3). G, H Apoptotic loss of SGCs was detected in two groups and higher TUNEL fluorescence (green color) ratio of SGCs area was detected in 12 M mice than in 6 W mice between the same turn. Blue shows DAPI staining of the nucleus. Scale bar = 50 μm. I, J Western blot analyses of laminb1 and H3K4me3 in the cochleae from 6 W (n = 6) and12 M (n = 6) mice. The statistical significance was represented as * p < 0.05; **p < 0.01; ***p < 0.001;****p < 0.0001. Bar graph results are means ± SD from 3 independent experiments