Noise exposure increased HSP70 immunoreactivity in the Deiters cells of B6 mice. Immunoreactivity was noted in cochleae from sham-exposed B6 mice (panels A, C and E) as well as in cochleae from noise-exposed B6 mice (panels B, D and F). Light reactivity was evident in type I fibrocytes of the cochlear lateral wall in sham-exposed (panel A, I) and noise exposed B6 mice (panel B, I). No difference in the intensity of the immunoreactivity was noted in the sham-exposed and noise-exposed cochlea in the region of the inner hair cell (arrow, panels C and D) or outer hair cells (arrowhead, panels C and D). However, increased expression of HSP70 was detected in the Deiter cells (D) after noise exposure. (panel D vs C). The reactivity noted in the fibrocytes of the spiral limbus (SpL) and in the cochlear nerve fibers (CN) in the sham-exposed mice was unchanged by noise exposure (panels E and F). No immunoreactivity was detected in any of these cochlear sites when the primary antibody was omitted (data not shown). I=type I fibrocytes, D=Deiter cells, SpL=spiral limbus, CN=cochlear nerve.