Figure 1.

Both kanamycin/furosemide and noise exposure result in profound hearing loss and hair cell death. a, c, All three genotypes have normal ABR thresholds prior to noise exposure or saline injection (black line). ABR thresholds are permanently elevated without any evident recovery after cochlear damage induced by either aminoglycoside injection (a) or noise over exposure (c). ( ) indicate that mice did not respond to any stimulus frequency. Data expressed as mean±SD. n=4-9 for each genotype for either injury model. Statistical significance computed using two-way ANOVA followed by Tukey’s multiple comparisons test yielded highly significant (p<0.0001) effect of days and frequency. Difference among genotypes prior noise exposure or saline injection and at several times post injury is not significant. b, d, Representative confocal images of cochlear whole mounts immunolabeled for hair cells (Myosin VIIa) from CX₃CR1^+/+ mice injected with kanamycin/furosemide (KF) (b) or exposed to loud noise (d) demonstrate extensive loss of both inner and outer hair cells in all the frequency regions of the cochlea. dB SPL, decibel sound pressure level; kHz, kilohertz; OHC, outer hair cell; IHC, inner hair cell; dpi, days post injection; DPNE, days post noise exposure. Scale=55μm