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Structural changes in the round window membrane following exposure to escherichia coli lipopolysaccharide and hydrocortisone
Author(s) -
Hellstrom Sten,
Spandow Odd,
Anniko Matti
Publication year - 1990
Publication title -
the laryngoscope
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.181
H-Index - 148
eISSN - 1531-4995
pISSN - 0023-852X
DOI - 10.1288/00005537-199009000-00014
Subject(s) - lipopolysaccharide , escherichia coli , bacterial outer membrane , ultrastructure , thickening , chemistry , hydrocortisone , epithelium , round window , biophysics , microbiology and biotechnology , biology , medicine , anatomy , endocrinology , inner ear , pathology , biochemistry , polymer science , gene
The present study focused on structural changes of the round window membrane (RWM) from agents that evoke transient or permanent impairment of the auditory brain‐stem response when applied into the RW niche. Escherichia coli (E. coli) lipopolysaccharide (LPS) in sterile water (SW) and a 2% suspension of hydrocortisone (CORT), micronized in SW, were instilled into the round window (RW) niche of Sprague‐Dawley rats. The morphology of the RWM was analyzed 3 to 21 days after instillation of either substance. Both substances caused minor structural alterations at the light microscopic level. The RWM showed a slight thickening and an invasion of inflammatory cells. At the ultra‐structural level, the CORT‐treated specimens showed an increased epithelial height and numerous microviUi, whereas the epithelium of the LPS‐treated specimens was extended and contained few microvilli resembling those in the normal RWM. We postulate that the RWM may undergo dynamic structural changes when exposed to various agents. The structural alterations per se can influence the passage of substances from the middle ear to the inner ear.