Figure 4
FM1-43 uptake in transgenic mouse cochlear hair cells. (A) FM1-43 uptake of Tg[PTmc1::Tmc2]; Tmc1∆/∆ cochleae (apical turns) at P12 (n = 3 mice), P16 (n = 3 mice) and P25 (n = 3 mice). FM1-43 uptake was observed both in inner HCs and outer HCs of Tg[PTmc1::Tmc2]; Tmc1∆/∆ cochleae at P12. In inner HCs, the uptake decreased with age and was limited at P25, while it remained detectable in outer HCs (Scale bar, 50 µm). (B) FM1-43 uptake of Tg[PTmc1::Tmc1]; Tmc1∆/∆ cochleae (n = 4 mice) at P25 (apical turn). FM1-43 uptake was observed in inner and outer HCs. (C) FM1-43 uptake of Tg[Tmc1∆Ex8_9]; Tmc1∆/∆ cochleae (n = 3 mice) at P12 (apical turn). FM1-43 uptake was not observed in inner or outer HCs. (D) The mean number ( ± SD) of inner HCs in which FM1-43 uptake was observed per 200 µm length of cochlear duct is shown for Tg[PTmc1::Tmc2]; Tmc1∆/∆ (black line), Tmc1∆/∆ (dotted line) or wild-type (Tmc1+/+, dashed line) cochleae at P12, P16 and P25. The number of outer HCs with FM1-43 uptake in Tg[PTmc1::Tmc2]; Tmc1∆/∆ cochleae remained constant and not significantly different from those in wild-type cochleae (one-way ANOVA, P > 0.05) and significantly higher than the value in Tmc1∆/∆ cochleae (one-way ANOVA, P < 0.001) at P12, P16 and P25. (E) The mean number ( ± SD) of inner HCs in which FM1-43 uptake was observed per 200 µm length of cochlear duct is shown for Tg[PTmc1::Tmc2]; Tmc1∆/∆ (black line), Tmc1∆/∆ (dotted line) or wild-type (Tmc1+/+, dashed line) cochleae at P12, P16 and P25. The number of inner HCs with FM1-43 uptake in Tg[PTmc1::Tmc2]; Tmc1∆/∆ cochleae declined with age and disappeared at P25. It is significantly smaller than the value in wild-type cochleae at P16 (one-way ANOVA, P < 0.01) and is not significantly different from those of Tmc1∆/∆ cochleae (one-way ANOVA, P > 0.05). IHC, inner hair cells; OHCs, outer hair cells.
