The pathological change of cochlear hair cell after exposure to intensive noise

Objective To assess the damage to cochlear hair cell,hair-bundle,body and nucleus after exposure to intensive noise to provide reference method for correctly evaluate the pathological condition of hair cell.Methods The normal hearing guinea pigs,weight 250-300g,were exposed for 200 times to impulse noise at 170 dB sound pressure level(SPL).Then the cochlea were examined microscopically by immunohistological method as well as scanning electron microscopy and transmission electron microscopy.Results After noise exposure,the majority of hair-bundle disappeared,and only a few cuticular plate remained.At the same time,the nuclear disintegrated and disappeared;but the much of hair cell body were intact,while there were some changes such as swelling and deformation.Conclusion After the noise damage the cochlea,the hair-bundle and nuclear are first damaged,then the cell body.The hair-bundle and nuclear are sensitive to damage.In addition,the results show that loss of the hair-bundle does not mean the loss of hair cells.So,it is not comprehensive that if we simply use a kind of morphological indicator to evaluate the hair cell damage.