In vivo iPSC differentiation. Immunohistochemical analysis of neuronal markers (nestin) in ICR mouse cochleae at 4 weeks after transplantation. CM-Di1-positive iPSCs were found in the modiolus (arrowheads in E). Blue fluorescence shows nuclear labelling with 4’,6-diamino-2-phenyl-indole (DAPI). Inside the modiolus, red fluorescence-labelled iPSCs expressed neuronal markers, nestin. Scale bars = 100 μm (A-D), 500 μm (E). ST, scala tympani; SM, scala media; SV, scala vestibuli; MO, modiolus.