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The influence of pneumococcal otitis media on the cochlear lateral wall
I Ichimiya1, M Suzuki, T Hirano
1Department of Otolaryngology, Oita Medical University, Japan.
Abstract:
The cochlear influence of otitis media was investigated in order to identify damaged regions causing cochlear malfunction. BALB/c mice were challenged with viable Streptococcus pneumoniae into the middle ear cavity and were killed 1 day to 1 month later for immunohistochemical analysis. Otitis media was induced in all of the animals, and some showed inflammatory cells in the cochlea. Although other changes were not obvious by hematoxylin and eosin staining, immunohistochemistry showed the presence of fibrinogen in the cochlea, mainly in the lower portion of the spiral ligament and in the spiral limbus. Immunostaining for connexin 26 was decreased in the spiral ligament, accompanied by marked fibrinogen staining. Immunostaining for sodium-potassium-adenosine triphosphatase in the stria vascularis and in the type II fibrocytes of the spiral ligament was not affected obviously. The presence of fibrinogen in the cochlea suggests disruption of the blood-labyrinth barrier caused by the middle ear inflammation. Changes in connexin 26 staining suggest the possibility that the spiral ligament could be among the regions responsible for the cochlear malfunction.
Insights
Otitis media can damage the cochlea, potentially affecting hearing. This study found fibrinogen in the cochlea and decreased connexin 26 in the spiral ligament, suggesting this area may cause cochlear malfunction.
Area of Science:
- Otolaryngology
- Neuroscience
- Pathology
Background:
- Otitis media is a common middle ear infection.
- Cochlear malfunction can result from middle ear inflammation.
Purpose of the Study:
- To investigate cochlear changes associated with otitis media.
- To identify specific damaged regions causing cochlear malfunction.
Main Methods:
- Induction of otitis media in BALB/c mice using Streptococcus pneumoniae.
- Immunohistochemical analysis of cochlear tissues at various time points.
- Staining for fibrinogen, connexin 26, and sodium-potassium-adenosine triphosphatase.
Main Results:
- Otitis media induced inflammation in the cochlea in some mice.
- Fibrinogen was detected in the spiral ligament and spiral limbus.
- Decreased connexin 26 staining was observed in the spiral ligament.
- Sodium-potassium-adenosine triphosphatase levels remained unaffected.
Conclusions:
- Fibrinogen presence suggests a disrupted blood-labyrinth barrier due to middle ear inflammation.
- Reduced connexin 26 in the spiral ligament indicates it may be a key region responsible for cochlear malfunction in otitis media.