Expression of intercellular adhesion molecule-1 in rat inner ear due to bacterial otitis media

Expressions of anti-Streptococcus pneumoniae antibody and anti-intercellula r adhesion molecule-1 (ICAM-1) antibody in the inner ear were studied immun ohistochemically in rats following inoculation of S pneumoniae type 6A into the middle ear cavity. Positive staining with anti-S pneumoniae antibody w as detected in the marginal cells of the stria vascularis of rats sacrifice d 3 days after S pneumoniae inoculation, but almost no staining was detecte d in those sacrificed at 14 days. Strong ICAM-1 expression was detected in the basal cell layer of the stria vascularis of rats sacrificed 3 days afte r inoculation, but the intensity of the staining had decreased by 14 days. These results suggest that the stria vascularis may be a site of the inner ear damage that follows bacterial inoculation into the middle ear cavity. T he up-regulated expression of ICAM-1 in the basal cell layer may represent a reaction of the inner ear to the bacterial otitis media.