Elsevier

Neuroscience

Volume 168, Issue 1, 16 June 2010, Pages 288-299
Neuroscience

Pain Mechanisms and Sensory Neuroscience
Research Paper
Salicylate-induced degeneration of cochlea spiral ganglion neurons-apoptosis signaling

https://doi.org/10.1016/j.neuroscience.2010.03.015Get rights and content

Abstract

Aspirin, whose active ingredient is sodium salicylate, is the most widely used drug worldwide, but it is not recommended for children because it may cause Reye's syndrome. High doses of salicylate also induce temporary hearing loss and tinnitus; while these disorders are believed to disappear when treatment is discontinued some data suggest that prolonged treatment may be neurotoxic. To investigate its ototoxicity, immature, postnatal day 3 rat cochlear organotypic cultures were treated with salicylate. Salicylate did not damage the sensory hair cells, but instead damaged the spiral ganglion neurons (SGN) and their peripheral fibers in a dose-dependent manner. The cross-sectional area of SGN decreased from 205 μm2 in controls to 143, 116, and 91 μm2 in cultures treated with 1, 3, or 5 mM salicylate, respectively. Morphological changes and caspase upregulation were indicative of caspase-mediated apoptosis. A quantitative RT-PCR apoptosis array identified a subset of genes up- or down regulated by salicylate. Eight genes showed a biologically relevant change (P<0.05, ≥2 fold change) after 3 h treatment with salicylate; seven genes (Tp53, Birc3, Tnfrsf5, Casp7, Nfkb1, Fas, Lta, Tnfsf10) were upregulated and one gene (Pycard) was downregulated. After 6 h treatment, only one gene (Nol3) was upregulated and two genes were downregulated (Cideb and Lhx4) while after 12 h treatment, two genes (Il10, Gadd45a) were upregulated and 4 (Prok2, Card10, Ltbr, Dapk1) were downregulated. High doses of salicylate in a physiologically relevant range can induce caspase-mediated cell death in immature SGN; changes in the expression of apoptotic genes particularly among members of the tumor necrosis factor (TNF) family appear to play an important role in the degeneration.

Section snippets

Cochlear cultures

Cochlear organotypic cultures were prepared from postnatal day 3 SASCO Sprague–Dawley rats as previously described (Ding et al., 2002, McFadden et al., 2003). Following decapitation, the cochlea was carefully removed and the organ of Corti and SGN were isolated and transferred onto rat tail collagen gel (type I rat-tail collagen (Collaborative Research, 3.76 mg/ml in 0.02 N acetic acid), 10×BME (basal medium Eagle) with 2% sodium carbonate in a 9:1:1 ratio). A 15-μL drop of the collagen gel was

SS damages nerve fibers

Fig. 1A–D illustrates the typical status of the hair cells and nerve fibers in control medium and cultures treated with 1, 3, or 5 mM of SS for 48 h or 10 mM SS for 96 h. Three rows of OHC and one row of IHC were present in the controls; many nerve fiber fascicles project radially and end near the IHC; a few fibers also project to the OHC (Fig. 1A). Treatment with 1 mM SS had no noticeable effect on OHC or IHC; however, the density of nerve fiber fascicles projecting towards the hair cells was

Discussion

The 1 and 3 mM doses of SS used this study are comparable to those observed in cochlear perilymph and cerebrospinal fluid of animals with hearing loss and tinnitus induced by systemic administration of a high dose of salicylate (Jastreboff et al., 1986, Jastreboff et al., 1988, Boettcher and Salvi, 1991, Lobarinas et al., 2006, Yang et al., 2007, Sun et al., 2009). Our results indicate that SS causes a dose-dependent shrinkage of SGN soma, a morphological feature of cells undergoing apoptosis,

Conclusion

Aspirin, whose active component is salicylate, is one of the most widely used over-the-counter medications; however, its is not recommended for use in children since it has been implicated in Reye's syndrome, a childhood disorder characterized by encephalopathy and hyperammonemia (Trost and Lemasters, 1997, Lemberg et al., 2009). Millions of patients (e.g. rheumatoid arthritis) chronically self-administer high doses of the aspirin for pain relief, inflammation and other health problems. High

Acknowledgments

Supported in part by grants from NIH (R01DC009091; R01DC009219) and Tinnitus Research Initiative.

References (104)

  • D. Ding et al.

    Leupeptin protects cochlear and vestibular hair cells from gentamicin ototoxicity

    Hear Res

    (2002)
  • E. Feinstein et al.

    Assignment of DAP1 and DAPK—genes that positively mediate programmed cell death triggered by IFN-gamma—to chromosome regions 5p122 and 9q341, respectively

    Genomics

    (1995)
  • J. Gross et al.

    Expression of prestin mRNA in the organotypic culture of rat cochlea

    Hear Res

    (2005)
  • M.C. Hollander et al.

    Analysis of the mammalian gadd45 gene and its response to DNA damage

    J Biol Chem

    (1993)
  • H. Hsu et al.

    TNF-dependent recruitment of the protein kinase RIP to the TNF receptor-1 signaling complex

    Immunity

    (1996)
  • N. Itoh et al.

    The polypeptide encoded by the cDNA for human cell surface antigen Fas can mediate apoptosis

    Cell

    (1991)
  • T.T. Jung et al.

    Ototoxicity of salicylate, nonsteroidal antiinflammatory drugs, and quinine

    Otolaryngol Clin North Am

    (1993)
  • S. Kasibhatla et al.

    Regulation of fas-ligand expression during activation-induced cell death in T lymphocytes via nuclear factor kappaB

    J Biol Chem

    (1999)
  • M. Levine et al.

    Chest pain and arthritis

    J Emerg Med

    (2005)
  • X. Liu et al.

    DFF, a heterodimeric protein that functions downstream of caspase-3 to trigger DNA fragmentation during apoptosis

    Cell

    (1997)
  • Y. Liu et al.

    cDNA cloning, chromosomal localization and expression pattern analysis of human LIM-homeobox gene LHX4

    Brain Res

    (2002)
  • K.J. Livak et al.

    Analysis of relative gene expression data using real-time quantitative PCR and the 2(-Delta Delta C(T)) Method

    Methods

    (2001)
  • A.A. Lugovskoy et al.

    Solution structure of the CIDE-N domain of CIDE-B and a model for CIDE-N/CIDE-N interactions in the DNA fragmentation pathway of apoptosis

    Cell

    (1999)
  • M. MacFarlane

    TRAIL-induced signalling and apoptosis

    Toxicol Lett

    (2003)
  • K. Machinis et al.

    Syndromic short stature in patients with a germline mutation in the LIM homeobox LHX4

    Am J Hum Genet

    (2001)
  • J. Masumoto et al.

    ASC, a novel 22-kDa protein, aggregates during apoptosis of human promyelocytic leukemia HL-60 cells

    J Biol Chem

    (1999)
  • L.M. McAllister-Lucas et al.

    Bimp1, a MAGUK family member linking protein kinase C activation to Bcl10-mediated NF-kappaB induction

    J Biol Chem

    (2001)
  • T.P. McDade et al.

    Salicylates inhibit NF-kappaB activation and enhance TNF-alpha-induced apoptosis in human pancreatic cancer cells

    J Surg Res

    (1999)
  • D. McFadden et al.

    Temporary hearing loss induced by combinations of intense sounds and nonsteroidal anti-inflammatory drugs

    Am J Otolaryngol

    (1984)
  • S.L. McFadden et al.

    M40403, a superoxide dismutase mimetic, protects cochlear hair cells from gentamicin, but not cisplatin toxicity

    Toxicol Appl Pharmacol

    (2003)
  • B.G. Peng et al.

    Aspirin selectively augmented N-methyl-d-aspartate types of glutamate responses in cultured spiral ganglion neurons of mice

    Neurosci Lett

    (2003)
  • N.D. Perkins

    The Rel/NF-kappa B family: friend and foe

    Trends Biochem Sci

    (2000)
  • O. Stoss et al.

    Alternative splicing determines the intracellular localization of the novel nuclear protein Nop30 and its interaction with the splicing factor SRp30c

    J Biol Chem

    (1999)
  • W. Sun et al.

    Salicylate increases the gain of the central auditory system

    Neuroscience

    (2009)
  • L.C. Trost et al.

    Role of the mitochondrial permeability transition in salicylate toxicity to cultured rat hepatocytes: implications for the pathogenesis of Reye's syndrome

    Toxicol Appl Pharmacol

    (1997)
  • H.T. Wang et al.

    Sodium salicylate reduces inhibitory postsynaptic currents in neurons of rat auditory cortex

    Hear Res

    (2006)
  • L. Wang et al.

    PYPAF7, a novel PYRIN-containing Apaf1-like protein that regulates activation of NF-kappa B and caspase-1-dependent cytokine processing

    J Biol Chem

    (2002)
  • A.H. Wyllie et al.

    Cell death: the significance of apoptosis

    Int Rev Cytol

    (1980)
  • T. Abe et al.

    Developmental expression of the outer hair cell motor prestin in the mouse

    J Membr Biol

    (2007)
  • B.B. Aggarwal et al.

    Human tumour necrosis factors: structure and receptor interactions

    Ciba Found Symp

    (1987)
  • B.B. Aggarwal et al.

    Characterization of receptors for human tumour necrosis factor and their regulation by gamma-interferon

    Nature

    (1985)
  • A.S. Baldwin

    Series introduction: the transcription factor NF-kappaB and human disease

    J Clin Invest

    (2001)
  • F.A. Boettcher et al.

    Concentration of salicylate in serum and perilymph of the chinchilla

    Arch Otolaryngol Head Neck Surg

    (1990)
  • G.-D. Chen et al.

    Too much of a good thing: long-term treatment with salicylate strengthens outer hair cell function but impairs auditory neural activity

    Hear Res

    (2010, Mar 11)
  • X. Chen et al.

    Differential roles of RelA (p65) and c-Rel subunits of nuclear factor kappa B in tumor necrosis factor-related apoptosis-inducing ligand signaling

    Cancer Res

    (2003)
  • M.Y. Cheng et al.

    Prokineticin 2 transmits the behavioural circadian rhythm of the suprachiasmatic nucleus

    Nature

    (2002)
  • T.O. Cheng

    The history of aspirin

    Tex Heart Inst J

    (2007)
  • G.M. Cohen

    Caspases: the executioners of apoptosis

    Biochem J

    (1997)
  • P.D. Crowe et al.

    A lymphotoxin-beta-specific receptor

    Science

    (1994)
  • M. Degli-Esposti

    To die or not to die—the quest of the TRAIL receptors

    J Leukoc Biol

    (1999)
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