Immunostaining for GFP positive cells in GRP reporter mice following noise exposure and LPS. Each column shows the basal-most three half turns of an ear from a mouse that was exposed to a 100 dB noise (left column) or to intraperitoneal LPS injection (right column). Open arrowheads indicate type I fibrocytes, closed arrowheads indicate type II fibrocytes. Open arrows indicate fibrocytes in the spiral limbus. Closed arrows indicate epithelial cells on the basilar membrane. In panel A, IP indicates inner pillar cell; DC indicates Deiters cell. Calibration bar in C is 100 μm.

NF-κB activation following noise exposure. A. Immunostaining for GFP in reporter a mouse that was perfused 24 hours following exposure to a 100 dB 8-16 kHz noise for two hours. B. Same case as shown in A except this ear had a conductive hearing loss. Calibration bar in A applies to A and B and indicates 40 microns. C. Immunostaining for p65 in the spiral ligament of a normal CBA mouse that was exposed to 100 dB 8-16 kHz noise for 1 hour and immediately sacrificed. The positive cells within the ellipse are type I fibrocytes with their nuclei stained. In contrast, root cells show their characteristic cytoplasmic staining. Insets show higher magnification of the indicated regions showing exclusive nuclear staining of type I fibrocytes (above) and lack of nuclear staining in roots cells, indicated by asterisks (below). The calibration bar indicates 10 microns and applies to both higher magnification images.

Fluorescent micrographs of GFP in NF-κB reporter mice (A-D). A. Spiral ligament in the lower basal turn of a mouse exposed to 100 dB noise for 2 hours and sacrificed 24 hours post-exposure. Most of the fluorescent cells are type I fibrocytes. The arrow indicates a rare fluorescent marginal cell of the stria vascularis. For orientation, see panel E. B. GFP fluorescent Deiters cells in a control mouse that was not exposed to noise or inflammatory stress. This is a rare case in which 3 adjacent Deiters cells were fluorescent. The arrow indicates the head of an outer pillar cell. C. Co-localization of green GFP fluorescence and red fluorescence reporting anti-GFP. D. A type II fibrocyte in a reporter mouse that was injected with LPS 24 hours prior to sacrifice showing green GFP fluorescence that was largely in different cellular compartments from the red immunostaining for GFP. E. A semithin section stained with osmium and toluidine blue showing the major structures of the cochlear duct. Outer hair cells (OHC), which are sensory cells, rest upon Dieters cells. The lateral wall of the duct is formed by the spiral ligament. Within the ligament the characteristic locations of type I and type II fibrocytes are indicated. The spiral limbus is situated toward the center of the cochlea.

Fluorescent micrographs contrasting the localization of NF- B activation in type I and type II fibrocytes. A. Image of GFP fluorescent type I fibrocytes (green) of a noise exposed mouse merged with red type II fibrocytes and stria vascularis. The latter structures are immunopositive for Na⁺, K⁺,-ATPase. (See Fig. 1D for key.) B. Merged image of GFP fluorescent type II fibrocytes in a mouse injected with 50 μg LPS. The type II fibrocytes appear yellow because they are also positive for Na⁺, K⁺,-ATPase, which is red as in panel C.