Fig. 3: DX-52-1-induced effects on sound-evoked motions of outer hair cell stereocilia.

a Time-resolved confocal images acquired during sound stimulation show that DX-52-1 does not alter the morphology of stereocilia (except for a small change in the brightness of the fluorescent dye). b Sound-evoked motion of the bundle tip (red) and base (blue) before and after DX-52-1 injection in an example preparation. The stimulus was a pure tone at 220 Hz and 80 dB sound pressure level. By subtracting trajectories from the tips and bases of stereocilia, a measure of the deflection of the bundle is obtained (green). c Confocal image obtained after DMSO injection, showing lack of effect on stereocilia morphology. d No change in the motion of the bundle tip (red) and base (blue) before and after DSMO injection observed along with absence of change in deflection (green). e–g Averaged bundle motion change at the base of outer hair cell stereocilia (blue bar), at their tip (red bar) and the deflection of the bundle (green bar). Data were normalized to the base trajectory amplitude recorded before the injection. Averaged data from 70 (DX-52-1) and 15 (DMSO) individual preparations ±standard deviation. h Time course of deflection amplitude of outer hair cell bundles (blue circle) in an example preparation. The vertical line at time zero indicates the time of injection. Data were normalized to the average trajectory amplitude recorded before injection. i High-resolution confocal images of stereocilia in preparations treated with DX-52-1 or vehicle show no detectable morphological changes. ****P < 0.0001; ***P < 0.001; **P < 0.01; *P < 0.05; n.s., not significant; two-tailed paired t-test, two-tailed unpaired t-test with Welch’s correction.