Treatment with dexamethasone arrests the development of myringosclerosis after myringotomy.
OBJECTIVE
To attempt to inhibit the development of myringosclerosis by intraperitoneal injection of dexamethasone.


BACKGROUND
The authors' earlier report showed that the development of myringosclerosis after myringotomy was associated with an inflammatory reaction. The present study was performed to secure evidence for this hypothesis.


METHODS
Three groups of bilaterally myringotomized rats were treated at 12-hour intervals with intraperitoneal injection of dexamethasone, RU486 (a glucocorticoid receptor antagonist), and saline, respectively. At 6, 12, 24, and 48 hours after the myringotomy, 2 animals were anesthetized on each occasion and examined otomicroscopically. The animals were then killed, and the tympanic membranes were excised and prepared for light microscopic studies.


RESULTS
Dexamethasone treatment retarded and diminished the development of sclerotic lesions markedly. Moreover, no inflammatory signs were seen in the flaccida specimens. When the RU486-treated animals were compared with the animals in the control group, there were no evident differences concerning the development of myringosclerosis or the extent of the inflammatory reaction.


CONCLUSIONS
These findings confirm the earlier hypothesis that an inflammatory reaction in collagen tissue is involved in the mechanism that causes the development of myringosclerosis.
Mattsson
C
C
Department of Otorhinolaryngology, Umeå University Hospital, Sweden.
Stierna
P
P
Hellström
S
S
D000818:Animals; D000893:Anti-Inflammatory Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D003907:Dexamethasone / Q000008:administration & dosage / Q000627:therapeutic use*; D007263:Infusions, Parenteral; D008264:Macrophages / Q000378:metabolism; D008297:Male; D008876:Middle Ear Ventilation / Q000009:adverse effects*; D015735:Mifepristone / Q000494:pharmacology / Q000627:therapeutic use; D051381:Rats; D017207:Rats, Sprague-Dawley; D011965:Receptors, Glucocorticoid / Q000037:antagonists & inhibitors; D012598:Sclerosis / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D014432:Tympanic Membrane / Q000378:metabolism / Q000473:pathology* / Q000601:surgery*
D000893:Anti-Inflammatory Agents; D011965:Receptors, Glucocorticoid; D015735:Mifepristone; D003907:Dexamethasone