Preliminary studies on differential expression of auditory functional genes in the brain after repeated blast exposures

J Rehabil Res Dev. 2012;49(7):1153-62. doi: 10.1682/jrrd.2011.09.0182.

Abstract

The mechanisms of central auditory processing involved in auditory/vestibular injuries and subsequent tinnitus and hearing loss in Active Duty servicemembers exposed to blast are not currently known. We analyzed the expression of hearing-related genes in different regions of the brain 6 h after repeated blast exposures in mice. Preliminary data showed that the expression of the deafness-related genes otoferlin and otoancorin was significantly changed in the hippocampus after blast exposures. Differential expression of cadherin and protocadherin genes, which are involved in hearing impairment, was observed in the hippocampus, cerebellum, frontal cortex, and midbrain after repeated blasts. A series of calcium-signaling genes that are known to be involved in auditory signal processing were also found to be significantly altered after repeated blast exposures. The hippocampus and midbrain showed significant increase in the gene expression of hearing loss-related antioxidant enzymes. Histopathology of the auditory cortex showed more significant injury in the inner layer compared to the outer layer. In summary, mice exposed to repeated blasts showed injury to the auditory cortex and significant alterations in multiple genes in the brain known to be involved in age- or noise-induced hearing impairment.

MeSH terms

  • Animals
  • Auditory Cortex / physiopathology*
  • Auditory Diseases, Central / genetics*
  • Auditory Diseases, Central / metabolism
  • Blast Injuries / physiopathology*
  • Brain Injuries / physiopathology
  • Cadherins / genetics
  • Cadherins / metabolism
  • Calcium-Binding Proteins / genetics
  • Calcium-Binding Proteins / metabolism
  • Explosions
  • GPI-Linked Proteins / genetics
  • GPI-Linked Proteins / metabolism*
  • Hearing Loss, Noise-Induced / genetics*
  • Hearing Loss, Noise-Induced / metabolism
  • Hippocampus / metabolism*
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism*
  • Mice
  • Mice, Inbred C57BL
  • Oligonucleotide Array Sequence Analysis
  • Superoxide Dismutase / genetics
  • Superoxide Dismutase / metabolism

Substances

  • Cadherins
  • Calcium-Binding Proteins
  • GPI-Linked Proteins
  • Membrane Proteins
  • Otoa protein, mouse
  • otoferlin protein, mouse
  • Sod3 protein, mouse
  • Superoxide Dismutase