Figure 6

WT and mpv17^a9/a9 neuromasts show loss of hair cells and afferent innervation following mechanical overstimulation. (A–F) Maximum-intensity projections of confocal images showing neuromasts with Parvalbumin-labeled hair cells (blue) and Ribeye b-labeled presynaptic ribbons (magenta). Neurod:GFP-labeled afferent neurites are also shown (green). Unexposed control neuromasts are shown in (A; WT) and (D; mpv17^a9/a9); exposed neuromasts with normal morphology are shown in (B; WT) and (E; mpv17^a9/a9); and exposed neuromasts with disrupted morphology are shown in (C; WT) and (F; mpv17^a9/a9). Arrows indicate hair cells lacking afferent innervation. (G,H) Quantification of average hair cells per neuromast shows a trend of hair cell loss in exposed neuromasts (G), which is specific to disrupted neuromasts (H; **P = 0.0037). n = 32–66 fish (neuromasts L3, L4, and L5); N = 9 experimental trials. (I,J) The average percentage of hair cells with GFP-labeled contacts. We observed significant neurite retraction [I; **P = 0.0020 (WT); ***P = 0.0010 (mpv17^a9/a9)], which is also specific to disrupted neuromasts only [J; **P = 0.0039 (WT); **P = 0.0020 (mpv17^a9/a9)]. n = 15–30 fish (neuromasts L3, L4, and L5); N = 6 experimental trials. Scale bar: 5 μm. Error bars: SEM. “ns” = not significant.