Morphologic changes in round window membrane after topical hydrocortisone and dexamethasone treatment.
OBJECTIVE
Are all glucocorticoids supposed to have the same effect on the round window membrane?


BACKGROUND
Interest in glucocorticoids for topical treatment of inner ear diseases is increasing. The safety of such treatment should therefore be an important consideration before clinical use.


METHODS
In this study the authors investigated the morphology of the round window membrane after topical instillation of dexamethasone or hydrocortisone into the middle ear. Twenty Sprague-Dawley rats were used. Five rats received 5 doses, and five rats 10 doses, of 1 microg (20 microl) dexamethasone in the right ear, and five others were given 5 doses, and five rats 10 doses, of 2% (20 microl) hydrocortisone solution, also in the right ear. Membrane morphology was studied in both light microscopy and transmission electron microscopy. The thickness of exposed membranes was measured and compared with that of control membranes.


RESULTS
Thickening and microscopically signs of inflammation were observed in hydrocortisone-exposed membranes but not in dexamethasone-exposed membranes, which did not differ morphologically from those in control ears.


CONCLUSIONS
Although hydrocortisone has anti-inflammatory properties, it seems to provoke inflammation in the round window membrane after topical instillation. Dexamethasone had no such effects, however.
Nordang
Leif
L
Department of Otorhinolaryngology and Head and Neck Surgery, University Hospital, Uppsala, Sweden. leif.nordang@ent.uas.lul.se
Linder
Birgitta
B
Anniko
Matti
M
D000287:Administration, Topical; D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology* / Q000627:therapeutic use*; D001489:Basilar Membrane / Q000187:drug effects* / Q000473:pathology* / Q000648:ultrastructure; D003907:Dexamethasone / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use*; D004848:Epithelium / Q000187:drug effects / Q000648:ultrastructure; D006854:Hydrocortisone / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D008854:Microscopy, Electron; D051381:Rats; D017207:Rats, Sprague-Dawley; D012405:Round Window, Ear / Q000187:drug effects* / Q000473:pathology* / Q000648:ultrastructure
D000893:Anti-Inflammatory Agents; D003907:Dexamethasone; D006854:Hydrocortisone