Figure 7.

Hair cell regeneration is differentially suppressed during 72 h inhibitor exposure. Fish were treated with 400 μm neomycin for 1 h (triangles) or mock-treated (squares), and allowed to recover in each inhibitor for 72 h (open symbols, dotted lines) or in vehicle (filled symbols, solid lines). GFP+ hair cell counts were performed at 1, 24, 48, and 72 h following treatment. A, Fish treated with neomycin and subsequently with 5 μm flubendazole (open triangles) displayed essentially no hair cell regeneration, while controls (filled triangles) showed complete recovery by 72 h. Flubendazole alone (open squares) produce a small (and significant, p < 0.001) decrease in total hair cell number at 72 h (filled squares). B, Hair cell regeneration in fish treated with neomycin and then exposed to 10 μm topotecan (open triangles) is also virtually totally suppressed relative to controls (filled triangles). In addition, treatment with topotecan in control fish causes toxicity at 48 h and beyond (open squares vs filled squares). C, 5 μm fulvestrant (open triangles) modestly reduced the number of regenerated hair cells versus controls (filled triangles) following neomycin pretreatment (p < 0.01 at 48 and 72 h after neomycin treatment). Fish treated with fulvestrant alone (open squares) did not show any significant hair cell loss relative to mock-treated controls (filled squares). For each group, seven neuromasts were examined (n = 10 fish). Error bars indicate ±1 SD.