Fig. 1

Characterization of exosomes and their capacity to reduce hearing loss and decrease hair cell loss after neomycin damage in mice. A Western blot analysis of exosome markers Alix, CD9, CD63, and CD81 in MSCs and MSC-derived exosomes, and the negative intracellular protein marker GAPDH. B Transmission electron microscope (TEM) analysis of MSC-derived exosomes. Scale bar, 200 nm (left), 100 nm (middle) and 50 nm (right). C Size distribution of exosomes measured by nanoparticle tracking analysis (NTA). D Confocal microscopy image showing exosomes internalization by hair cells in vitro. Scale bar, 20 μm (left) and 10 μm (right). (E) Schematic diagram of animal experiment workflow, round window niche (RWN). F Analysis of ABR thresholds in mice treated with neomycin (Neo, 200 mg/kg for five consecutive days) and/or exosomes (Exo, 20 μg in 10 μl PBS). n = 6 mice G–I Immunofluorescence staining with Myo 7a (green), F-actin (red) and Hoechst (blue) in the apical (G), middle (H), and basal (I) turns of the cochleae from different groups. Scale bars, 50 μm. J Quantification of Myo 7a-positive hair cells in the apical, middle, and basal turns of the cochleae. The results were representative of the data generated in at least three independent experiments. The data were presented as mean ± s.d. n.s., not significant; *P < 0.05; **P < 0.01 by one-way ANOVA (F, J)