The cochlear pericytes

Objectives: Cochlear pericytes are not well characterized. The aim of this study was to further advance the characterization of cochlear pericyte location and distribution, with particular focus on pericyte-related proteins on the capillaries of the cochlear lateral wall that are functionally integral to structure, contraction, and gap junction transport. Materials and Methods: Cochlear pericytes were identified by the immunofluorescence labeling of pericyte marker proteins, including alpha-smooth muscle actin (α-SMA), desmin, Thy-1, tropomyosin, and NG2, and by morphological identification, using fluorescence, electron, and differential interference contrast microscopy. Results: Pericytes were predominately found in the capillary network of the cochlear lateral wall, with considerable morphological heterogeneity across different types of microvessels. For example, pericytes on the vessels of the spiral ligament (V/SL) strongly expressed a gap junction protein, connexin 40, and were positive for α-SMA, tropomyosin, and desmin. In contrast, pericytes on the vessels of the stria vascularis (V/SV) were positive for desmin, and were negative for α-SMA and tropomyosin. Conclusions: The capillary networks of the cochlear lateral wall comprise a rich population of pericytes. These pericytes are morphologically heterogeneous, with protein expression potentially indicative of function.