Melanocytes in the mouse inner ear and cells mistaken for melanocytes

Melanocytes are important components of the inner ear’s cellular architecture. However, limited morphological research has hindered a complete understanding of inner ear function. This study characterized the morphology of inner ear melanocytes and cells often misidentified as melanocytes. Immunofluorescence, Smart-seq, transmission/field emission scanning electron microscopy, and immunoelectron microscopy were used. Cells with a “black ball” appearance in the vestibule were identified as macrophages. We examined variation in melanocytes or macrophages with age, strain, and cisplatin injury. Kir4.1 expression and the greater noise resistance observed in pigmented mice suggest potential melanocyte functions. Based on melanin distribution in Pou3f4y/- mice, we hypothesize that melanocytes migrate from the modiolus along Reissner's membrane to the stria vascularis, following a base to apex gradient. These findings provide novel ultrastructural and immunological insights into inner ear function. Smart-RNA-seq profiling of Cells with a “black ball” appearance in the vestibule.