AGs differ in relative hair cell toxicity dependent on time of exposure and length of incubation. (A–C) Fish were treated with 200 μM neomycin (Neo) or gentamicin (Gent; red bar) for time indicated, or rinsed into fresh medium (blue bar). (A) Hair cells were exposed for 1 h acute treatment with AGs. Hair cells are effectively killed by Neo, but are largely spared by Gent. n = 9–11 fish, 4 NMs/fish. One-way ANOVA with Dunnet's post-hoc comparison to control, ****P-value < 0.0001. (B) Chronic 24 h treatment with Neo or Gent results in hair cell loss. n = 9–11 fish, 4 NMs/fish. One-way ANOVA with Dunnet's post-hoc comparison to control, ****P-value < 0.0001. (C) Substantial death occurs after 1 h treatment with Neo or Gent, rinsing, and then incubation for 23 h in fresh medium (1+23 h). n = 9–11 fish, 4 NMs/fish. One-way ANOVA with Dunnet's post-hoc comparison to control, ****P-value < 0.0001. (D) Dose-dependent loss of hair cells after treatment with neomycin for 1, 24, or 1+23 h. Differences between treatments were highly significant (2-way ANOVA, Tukey's multiple comparison, p < 0.0005). n = 9–11 fish, 4 NMs/fish for each condition. (E) Dose-dependent loss of hair cells after treatment with gentamicin for 1, 24, or 1+23 h. Differences between treatments were highly significant (2-way ANOVA, Tukey's multiple comparison, p < 0.0001). Post-hoc comparison of individual points are presented in Supplementary Tables 1, 2. n = 9–11 fish, 4 NMs/fish for each condition. Error bars represent Standard Deviation.
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