Expression of COX-2 and NMDA receptor genes at the cochlea and midbrain in salicylate-induced tinnitus§

Authors

  • Juen-Haur Hwang MD, MMS,

    1. Departments of Otolaryngology, Buddhist Dalin Tzu-Chi General Hospital, Chiayi, Taiwan
    2. School of Medicine, Tzu Chi University, Hualien, Taiwan
    3. Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
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  • Jin-Cherng Chen MD,

    1. Neurosurgery, Buddhist Dalin Tzu-Chi General Hospital, Chiayi, Taiwan
    2. School of Medicine, Tzu Chi University, Hualien, Taiwan
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  • Shan-Ying Yang MS,

    1. Department of Food and Nutrition, Providence University, Taiwan
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  • Ming-Fu Wang PhD,

    1. Department of Food and Nutrition, Providence University, Taiwan
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  • Tien-Chen Liu MD, PhD,

    Corresponding author
    1. Department of Otolaryngology, National Taiwan University Hospital, Taipei, Taiwan
    • Department of Otolaryngology, National Taiwan University Hospital, No. 7, Chung-Shan S. Road, Taipei 100, Taiwan
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  • Yin-Ching Chan PhD

    Corresponding author
    1. Department of Food and Nutrition, Providence University, Taiwan
    • Department of Food and Nutrition, Providence University, No. 200, Chungchi Rd., Shalu, Taichung 433, Taiwan
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  • The authors have no financial disclosures for this article.

  • The authors have no onflicts of interest to disclose.

  • §

    This study was supported by grants from the National Science Council, Taiwan (NSC-95-231693-B-126-008) and the Taichung Veterans General Hospital and Providence University (TCVGH-PU988104) Taichung, Taiwan.

Abstract

Objective/Hypothesis:

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.

Study Design:

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. Laryngoscope, 2011

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