Figure 2. Adjudin protects against gentamicin-induced hair cell loss in rat cochleae.

(A) Samples from the four treatment groups were labeled with Myosin VIIa (red, a–d) and Phalloidin (green, e–h), with the merged images shown in (i–l). Cochlear explant cultures were divided into four treatment groups: (1) no treatment control (a, e, i); (2) a culture treated with 0.05 mM gentamicin (b, f, j). Note that most of the hair cells were depleted; (3) a culture which was pretreated with 100 μM adjudin for one day and then challenged with 0.05 mM gentamicin in the presence of adjudin for another day (c, g, k); and (4) a culture which was treated with 100 μM adjudin for 2 days (d, h, l). Note that adjudin has little cytotoxicity itself. Bar = 10 μm. (B) Quantitative analysis of the number of hair cells in the different treatment groups as shown in the representative images in (A). (C) Adjudin reduces gentamicin induced-hair cell apoptosis. Cochlear explant cultures were divided into four groups: (a) control; (b) 0.05 mM gentamicin treatment (27 h); (c) Adjudin (100 μM) pretreatment for a day followed by 0.05 mM gentamicin challenge in the presence of adjudin for another 27 h; and (d) Adjudin (100 μM) treatment only as in (c). Phalloidin (red) labels hair cells whereas the green fluorescence indicates apoptotic hair cells (TUNEL). Bar = 10 μm. (D) Quantitative analysis of the number of apoptotic hair cells in the Organ of Corti. Data were collected from five or more cultures in each group and are expressed as means ± SEM. ***p < 0.001, *p < 0.05, one-way ANOVA followed by Tukey's multiple comparison test.