title: Expression of COX-2 and NMDA receptor genes at the cochlea and midbrain in salicylate-induced tinnitus.
abstract: OBJECTIVE
  The expression of the genes for cyclooxygenase (COX) and NMDA receptor (NR) has seldom been reported in tinnitus. We hypothesized that expression of COX-2 and NR was altered in the cochlea and midbrain in salicylate-induced tinnitus.
  
  
  METHODS
  Experimental study on mice.
  
  
  METHODS
  We evaluated the tinnitus score and mRNA expression levels of COX-2 and NR subtype 2B (NR2B) in the cochlea and midbrain in response to intraperitoneal injections of salicylate for 4 days.
  
  
  RESULTS
  At day 4 of tinnitus induction, the mean weights of the whole body and midbrain did not change greatly in both control and salicylate groups. The tinnitus score was not elevated from day 1 to day 4 in the control group, but increased day by day in the salicylate group. The mRNA expression level of COX-2 decreased slightly in the salicylate group in the cochlea (1.1 ± 0.33 vs. 1.3 ± 0.49, P = .0752) and in the midbrain (0.9 ± 0.10 versus 1.0 ± 0.35, P = .0489). Inversely, the expression levels of the NR2B gene increased moderately in the salicylate group in the cochlea (3.7 ± 0.47 versus 2.3 ± 1.13, P < 0.0001) and in the midbrain (1.6 ± 0.64 versus 1.0 ± 0.44, P = .0007).
  
  
  CONCLUSIONS
  Salicylate induced tinnitus and altered the expression of the COX-2 and NR2B genes in the cochlea and midbrain of mice. These findings might contribute to further understanding of pathophysiology and therapy of tinnitus.
authors.affiliation: Department of Otolaryngology, Buddhist Dalin Tzu-Chi General Hospital, Chiayi, Taiwan.
authors.forename: Juen-Haur
authors.initials: JH
authors.lastname: Hwang
authors.forename: Jin-Cherng
authors.initials: JC
authors.lastname: Chen
authors.forename: Shan-Ying
authors.initials: SY
authors.lastname: Yang
authors.forename: Ming-Fu
authors.initials: MF
authors.lastname: Wang
authors.forename: Tien-Chen
authors.initials: TC
authors.lastname: Liu
authors.forename: Yin-Ching
authors.initials: YC
authors.lastname: Chan
mesh_terms: D000818:Animals; D015139:Blotting, Southern; D003051:Cochlea / Q000737:chemistry*; D051546:Cyclooxygenase 2 / Q000235:genetics*; D015870:Gene Expression; D008297:Male; D008636:Mesencephalon / Q000737:chemistry*; D051379:Mice; D012333:RNA, Messenger / Q000032:analysis; D016194:Receptors, N-Methyl-D-Aspartate / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012459:Salicylates / Q000494:pharmacology*; D014012:Tinnitus / Q000139:chemically induced*
chemical_list: D012333:RNA, Messenger; D016194:Receptors, N-Methyl-D-Aspartate; D012459:Salicylates; C077623:Ptgs2 protein, mouse; D051546:Cyclooxygenase 2