Figure 6.

miTmc Gene Therapy Improves Hair Cell Survival

Wild-type, Tmc1^Bth/+, Tmc1^Bth/++miSafe, and Tmc1^Bth/++miTmc animals sacrificed 35 weeks after treatment. Ears were fixed, dissected, and stained as cochlear whole mounts.

(A) 10× images of representative whole-mount apical turns from wild-type, Tmc1^Bth/++miTmc, Tmc1^Bth/++miSafe, and Tmc1^Bth/+ animals. Samples were stained with MYO7A (red) and phalloidin (green) for labeling hair cells and filamentous actin, respectively. Arrowheads show the apical tip and 8 and 16 kHz regions along the apical turn of the cochlea. Note IHC preservation in the Tmc1^Bth/++miTmc animals. The white cross shows the area devoid of IHCs. Scale bars represent 150 μm.

(B) 40× magnification at the indicated position in relation to the cochlear apex. The three rows of OHCs (1–3), pillar cells (P), and IHCs are shown. Areas with dark hallows illustrate OHC or IHC loss. The white cross shows the area devoid of IHCs. Scale bars represent 50 μm.

(C and D) IHC (C) and OHC (D) survival was quantified with 20×–40× images of whole-mount cochlea compiled into cochleograms at 35 weeks. Hair cells were counted in 0.25 mm segments and plotted against the distance (%) from the apex. Tmc1^Bth/++miSafe, Tmc1^Bth/++miTmc, and Tmc1^Bth/++miTmc best performers (n = 2) are shown. ^∗p < 0.05, ^∗∗p < 0.005.