Reversible p53 inhibition prevents cisplatin ototoxicity without blocking chemotherapeutic efficacy (2016)
Figure 5

Figure 5. Genetic and pharmacological deletion of p53 prevents loss of hearing and hair cells in adult mice.

A Representative auditory brainstem response (ABR) waveforms evoked by 16 kHz tone-bursts in p53wt mice treated with saline (black plot) or CDDP (green plot), and p53-/- mice treated with saline (light blue plot) or CDDP (dark blue plot) for 5 days.

B ABR thresholds recorded in p53wt mice before (gray plot) and after 5 days of saline (black plot) or CDDP treatments (green plot), and ABR thresholds recorded in p53-/- mice before (light gray plot), and after 5 days of saline (light blue plot) or CDDP treatment (dark blue plot).

C Mean ABR threshold from 4 kHz to 32 kHz derived from B. Data are expressed as mean ± SEM (saline treated-group: n=7, CDDP treated-group: n=12). One-way ANOVA test followed by post hoc Tukey’s test (**P ≤ 0.008, p53wt+CDDP, d5 vs. p53wt, before or p53wt+CDDP, d5 vs. p53-/- + CDDP, d5).

D Representative scanning electron microscopy micrographs showing the basal regions of cochleae from CDDP-treated p53wt and p53-/- mice after 5 days. Scale bar=15µm.

E Cytocochleograms representing the percentage of surviving hair cells in four cochlear regions located at 1.1, 2.6, 3.5 or 4.1 mm from the cochlear apex provided from saline-treated p53wt mice (black bars), CDDP-treated p53wt mice (green bars) or p53-/- mice (blue bars), after 5 days (n=5 per group). Data are expressed as mean ± SEM. Kruskal–Wallis test followed by post hoc Dunn's test (**P ≤ 0.008, p53wt+CDDP, d5 vs. p53wt+saline, d5 or p53wt+CDDP, d5 vs. p53-/- + CDDP, d5).

F ABR thresholds from p53wt mice recorded prior to (gray plot) or after 5 days systemic treatment with: DMSO (yellow plot), CDDP+DMSO (green plot), CDDP+PFT-α (pink plot).

G Mean ABR threshold from 4 kHz to 32 kHz derived from F. Data are expressed as mean ± SEM (DMSO treated-group: n=7; CDDP+DMSO treated-group: n=12; CDDP+ PFT-α-treated group: n=12). One-way ANOVA test followed by post hoc Tukey’s test (***P ≤ 0.0005, CDDP+DMSO, d5 vs. before or CDDP+DMSO, d5 vs. CDDP+PFT-α, d5).

H Cytocochleograms representing the percentage of surviving hair cells in four cochlear regions located at 1.1, 2.6, 3.5 or 4.1 mm from the cochlear apical end taken from p53wt mice treated with: DMSO (yellow bars), CDDP+DMSO (green bars), CDDP+PFT-α (pink bars), after 5 days (n=5 per group). Data are expressed as mean ± SEM. Kruskal–Wallis test followed by post hoc Dunn's test (**P ≤ 0.008, CDDP+DMSO, d5 vs. DMSO, d5 or CDDP+DMSO, d5 vs. CDDP+PFT-α, d5).

I ABR thresholds from p53wt mice recorded prior to (gray plot and black plot for left and right ear, respectively) or after 5 days of systemic treatment with CDDP plus intratympanic injection of DMSO into the left ear (green plot), and of PFT-α into the right ear (pink plot).

J Mean ABR threshold from 4 kHz to 32 kHz derived from I. Data are expressed as mean ± SEM (n=14). One-way ANOVA test followed by post hoc Tukey’s test (***P = 0.0003 , CDDP+left ear, DMSO vs. before, left ear or CDDP + left ear, DMSO vs. CDDP + right ear, PFT-α.

K Cytocochleograms representing the percentage of surviving hair cells in four cochlear regions located at 1.1, 2.6, 3.5 or 4.1 mm from the cochlear apical end taken from the DMSO-treated left ear (green bars) and PFT-α treated right ear (pink bars) of the same CDDP-treated p53wt mice after 5 days (n=5 per group). Data are expressed as mean ± SEM. Kruskal–Wallis test followed by post hoc Dunn's test (**P ≤ 0.008, CDDP + right ear, PFT-α vs. CDDP+left ear, DMSO).