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Morphologic and biochemical study of vascular permeability of the middle ear mucosa in experimental otitis media
M Sakagami1, T Harada, S K Juhn
1Department of Otolaryngology, University of Minnesota Medical School, Minneapolis.
Abstract:
The vascular permeability of the middle ear mucosa of chinchillas was examined by light and electron microscopy using horseradish peroxidase (HRP). Two kinds of experimental otitis media were used: serous otitis media (SOM) produced by eustachian tube obstruction and purulent otitis media (POM) produced by inoculation with Streptococcus pneumoniae type 7F. Normal mucosa showed no leakage of HRP. In SOM, vessels were dilated and tortuous, but they did not show HRP leakage. In POM, vessel leakage of HRP was extensive. Biochemically, we measured the middle ear effusion-to-serum ratio of both albumin and alpha 2-macroglobulin by an immunodiffusion method. The ratios of the two marker proteins for vascular permeability were significantly higher in POM than in SOM. This suggests that POM increases vascular permeability to a higher degree than SOM, and morphologic findings in the middle ear mucosa correlate with the biochemical composition of the middle ear effusion.
Insights
Purulent otitis media (POM) significantly increases middle ear vascular permeability, unlike serous otitis media (SOM). This finding, observed in chinchilla models, highlights differences in vascular leakage during infection.
Area of Science:
- Otolaryngology
- Pathology
- Microbiology
Background:
- Middle ear infections, including serous otitis media (SOM) and purulent otitis media (POM), are common conditions.
- Understanding the changes in middle ear mucosa vascular permeability is crucial for diagnosing and treating these conditions.
Purpose of the Study:
- To investigate and compare the vascular permeability of middle ear mucosa in experimental SOM and POM in chinchillas.
- To correlate morphological findings with biochemical markers of vascular permeability.
Main Methods:
- Utilized light and electron microscopy with horseradish peroxidase (HRP) to assess vascular leakage in chinchilla middle ear mucosa.
- Induced experimental SOM via eustachian tube obstruction and POM via Streptococcus pneumoniae inoculation.
- Quantified middle ear effusion-to-serum ratios of albumin and alpha 2-macroglobulin using immunodiffusion.
Main Results:
- Normal middle ear mucosa showed no HRP leakage.
- SOM exhibited dilated and tortuous vessels but no significant HRP leakage.
- POM demonstrated extensive HRP leakage, indicating increased vascular permeability.
- Biochemical analysis revealed significantly higher effusion-to-serum ratios of albumin and alpha 2-macroglobulin in POM compared to SOM.
Conclusions:
- Purulent otitis media significantly elevates middle ear vascular permeability to a greater extent than serous otitis media.
- Morphological observations of middle ear mucosa correlate with biochemical measurements of vascular permeability in different otitis media models.