Ultrastructural changes to the cochlea resulting from impulse noise.
Slepecky-N; Hamernik-R; Henderson-D; Coling-D
Arch Oto-Rhino-Laryngol 1981 May; 230(3):273-278
Chinchillas were exposed to impulse noise from a compressed air driven source to determine the effects on the ultrastructure of the cochlea. Fifty impulses were presented, one per minute at an intensity of 155 decibels (dB) peak sound pressure level. In the regions of the cochlea where hair cells were present and appeared normal, there was damage to the sensory cells observed at the ultrastructural level which could account for the change in threshold sensitivity they demonstrated. Signs of cochlear pathology included an increase in lysosomes, multivesicular bodies, vacuolization, and disorganization of subsurface cisternae and proliferation of Hensen bodies. In the regions of the cochleas sectioned, there were similar changes in the ultrastructure of the hair cell somata in all experimental animals while the amount of threshold shift varied from 0 to 30dB. Hearing loss could not, therefore, be explained by these findings alone. Three of the four experimental animals showed ultrastructural changes to the stereocilia. There were alterations to the cell membrane which resulted in loosening and wrinkling of the membrane surrounding the stereocilia as well as fusion to form giant stereocilia. Changes were also noted in the filaments within the stereocilia as reflected in the loss of stiffness and in the disappearance of the rootlets.
NIOSH-Grant; Noise-induced-hearing-loss; Ears; Cell-damage; Laboratory-animals; Ultrastructure; Noise-exposure
Callier Ctr/communic Disorders Callier Center 1966 Inwood Road Dallas, Tex 75235
Archives of Oto-Rhino-Laryngology
University of Texas Dallas, Richardson, Texas