An increase in hair cells in the inner hair cell region after ATOH1 gene therapy.

<p>Example photomicrographs of surface preparations of the basal turn of the cochlea from (A) normal, (B) four day deaf, (C) Ad-GFP treated, (D) Ad-ATOH1 treated animals (red = myosinVIIa, green = GFP, blue = DAPI, dashed lines mark the sensory region, scale bar = 20 µm). (E) When quantified there was a significant loss of IHCs after four days of deafness compared to normal hearing animals. Three weeks post ATOH1-gene therapy there were significantly more myosinVIIa positive cells in the IHC region compared with the four day deaf group (*p<0.05, ANOVA). This number however remained below that observed in normal cochleae which had a greater number of IHCs compared to any other treatment group (#p<0.05, ANOVA). (F) A comparison of treated (injected) versus non-treated (contralateral) cochleae showed ATOH1-injected cochleae to have a significantly greater number of IHCs relative to the contralateral control cochleae (§p<0.05 paired t-test).