title: Changes in F-actin labeling in the outer hair cell and the Deiters cell in the chinchilla cochlea following noise exposure.
abstract: It has been found that 'conditioning' noise exposures can render the inner ear more resistant to traumatic noise exposures. To explore the possible mechanisms underlying this phenomenon, filamentous actin (F-actin), labeled by rhodamine-phalloidin, was examined in the chinchilla cochlea using confocal fluorescence microscopy. The conditioning noise was 0.5 kHz octave band noise (OBN) at 90 dB SPL for 6 h/day and the high-level noise was the same noise but at 105 dB SPL for 4 h. A variety of pathological changes were found in the chinchilla cochlea after exposure to noise. Subjects exposed to conditioning noise (1 day or 10 days) and only high-level noise showed an increase in F-actin labeling than unexposed controls. By contrast, subjects who had 5 days quiet after the 10-day conditioning exposure exhibited a decrease in F-actin labeling. Interestingly, subjects exposed to high-level noise with prior 10-day conditioning exposure also showed a decrease in F-actin labeling in the cuticular plate and the stereocilia. The F-actin decreases in the stereocilia and the cuticular plates may decrease the mechanical rigidity of the organ of Corti. A more pliable organ of Corti may have reduced the possibility of fracture or ripping of cell junctions during the motion of the basilar membrane induced by acoustic overstimulation.
authors.affiliation: Department of Communicative Disorders and Sciences, State University of New York at Buffalo, 14214, USA.
authors.forename: B H
authors.initials: BH
authors.lastname: Hu
authors.forename: D
authors.initials: D
authors.lastname: Henderson
mesh_terms: D000161:Acoustic Stimulation; D000199:Actins / Q000378:metabolism*; D000818:Animals; D001489:Basilar Membrane / Q000502:physiology; D002682:Chinchilla; D003051:Cochlea / Q000378:metabolism; D017629:Gap Junctions / Q000502:physiology; D018072:Hair Cells, Auditory, Outer / Q000378:metabolism* / Q000502:physiology; D007091:Image Processing, Computer-Assisted; D007150:Immunohistochemistry; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D017084:Otoacoustic Emissions, Spontaneous; D010590:Phalloidine / Q000737:chemistry / Q000378:metabolism; D012235:Rhodamines / Q000737:chemistry / Q000378:metabolism; D003689:Vestibular Nucleus, Lateral / Q000378:metabolism*
chemical_list: D000199:Actins; D012235:Rhodamines; D010590:Phalloidine