title: Effect of topical dexamethasone on sensorineural hearing loss in endotoxin-induced otitis media.
abstract: Sensorineural hearing loss, which is limited to the cochlear basal turn, due to acute or chronic otitis media has been reported in clinical and experimental studies. In the present study, the effect of intratympanic dexamethasone on endotoxin-induced cochlear damage was investigated by measuring the cochlear blood flow and hearing.
  
  
  METHODS
  Ten male Sprague-Dawley rats were inoculated with lipopolysaccharide (LPS), and divided into 2 groups of five rats each. One hour after intratympanic inoculation, the group A received 40 microl of phosphate-buffered saline (PBS) in the right middle ear cavity, group B received 40 microl of dexamethasone. The treated animals were examined 24 h after inoculation using auditory brainstem response (ABR) and cochlear blood flow (CBF).
  
  
  RESULTS
  The elevated threshold decreased significantly after intratympanic dexamethasone administration compared to the PBS-treated group. Intratympanic dexamethasone administration to the round window of rats led to a statistically significant increase in CBF compared to the PBS-treated group (p <0.05). The response to round window application of prostaglandin E1 (PGE1) in the dexamethasone-treated group was better than in the PBS-treated group.
  
  
  CONCLUSIONS
  Our results showed that intratympanic dexamethasone treatment was effective in protecting the function of the cochlea against endotoxin-induced otitis media.
authors.affiliation: Department of Otolaryngology, Chonnam National University Medical School, Gwangju, Dong-ku, South Korea. chulsavio@hanmail.net
authors.forename: Chul Ho
authors.initials: CH
authors.lastname: Jang
authors.forename: Yong Bum
authors.initials: YB
authors.lastname: Cho
authors.forename: Cheol Hee
authors.initials: CH
authors.lastname: Choi
authors.forename: See Young
authors.initials: SY
authors.lastname: Park
authors.forename: Sok Cheon
authors.initials: SC
authors.lastname: Pak
mesh_terms: D000287:Administration, Topical; D000818:Animals; D003907:Dexamethasone / Q000008:administration & dosage / Q000627:therapeutic use*; D004731:Endotoxins / Q000633:toxicity*; D034381:Hearing Loss / Q000139:chemically induced*; D008297:Male; D010033:Otitis Media / Q000139:chemically induced*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D004731:Endotoxins; D003907:Dexamethasone