Fig. 4.

Senescence-like phenotype upon H₂O₂ treatment. a Representative Western blot analysis using antibodies against p21, p38, p-p38, p16, p19, BubR1, and β-actin in whole cochlear extracts. b, c Histograms representing the levels of p21, p38, p-p38, p16, p19, and BubR1 in 0 (control), 0.4, and 0.5 mM H₂O₂-exposed groups (n = 6 cochleae per condition). β-Actin served as a loading control. Data are expressed as mean ± SEM. One-way ANOVA test followed by post hoc Tukey’s test (*P ≤ 0.05, **P ≤ 0.01, ***P ≤ 0.001 vs. H₂O₂ 0 mM). d Light microscope images showing the basal region of the organ of Corti cultures treated with either culture medium alone or containing 0.5 mM H₂O₂ for 5 h before their maintenance in culture medium alone for 3 days. The samples were then stained with fresh β-galactosidase (SA-β-gal) solution at pH 6.0. Note that H₂O₂ exposure resulted in an increased activity of SA-β-gal (blue) in OHCs and supporting cells located in the area of the organ of Corti as well as in the cells located in the region of the spiral ganglion (SG). Scale bar = 25 μm. All experiments were performed in triplicate