The Morphological Changes of the Cochlea in the Guinea Pig after Single Blast Wave Stimulation / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: The mechanism of the noise damage to the cochlea is not fully understood in spite of many studies. The morphological changes in a noise stimulated model show various features relating to the duration of the exposure and sound intensity. Until now there had been a lot of the morphological studies on noise induced hearing loss models, but only a few reports of single blast injury of more than 150 dB. MATERIALS AND METHOD: We observed with a transmission electron microscope by using the microslicing technique for minimizing the tissue injury and successful hair cell counting in resin embedded cochlea of the guinea pig, stimulated by a 178 dB single blast wave. RESULTS: The area of hair cell damage in L.M. showed stereocilia bending at 24 hours, proliferation of Hensen's body, subsurface cistern in outer hair cell and mitochondria proliferation in inner hair cell within 2wks. The area of no hair cell damage in L.M. showed minimal changes in E.M., as well. CONCLUSION: These results suggest that the 178 dB single blast wave injury may not cause severe distortion of the organ of Corti in the guinea pig and thus the compensation process can be advanced gradually.

Immune-mediated Inner Ear Dysfunction Caused by Histones, as Planted Target Antigens / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Histones, a set of highly cationic proteins essentially involved in the binding and packing of DNA in the cell nucleus chromatin, have five subclasses (H1, H2a, H2b, H3, H4) in mammalian animals. These components play the most important role in producing autoantibody in SLE and etc. Some studies proposed that there were a relationship between the activity of the disease and the titer of these autoantibody. Recently, histones were revealed to be involved in the immune deposit on GBM in MRL/lpr mice, and cause immune-mediated glomerulonephritis in normal animals. MATERIALS AND METHODS: We examined IgG deposition on the basement membrane of strial capillaries and recorded the endocochlear potential from the basal turn by an electrode inserted though the round window in guinea pigs which was injected by histone(H2a) and anti-histone antisera. RESULTS: IgG depositions were seen on the basement membrane of stria capillaries. IgG was also found to be accumulated on the extravascular side of the basement membrane. However, C3 was almost never observed in the stria vascularis of histone and the anti-histone antisera injected group. In these animals, intracellular edema was evident in the stria vascularis especially at the second and more apical turns but no inflammatory cell infiltration was present. The signifcant decrease in EP was observed just after the injection of anti-histone antisera in the animals receiving an intra-arterial injection of histones. CONCLUSION: This study indicated that cationic antigen could be trapped on the negatively charged basement membrane of strial capillaries, leading to the in situ immune complex formation, and eventually causing immune-mediated hearing loss.