Effects of Silica Exposure on Substance P Immunoreactivity and Preprotachykinin mRNA Expression in Trigeminal Sensory Neurons in Fischer 344 Rats

Details

• Personal Author:
  Castranova, Vincent ; Dey RD ; Hunter DD ; Stanley C
• Description:
  Trigeminal sensory neurons innervate the nasal cavity and may release substance P (SP) upon exposure to inhaled irritants. The purpose of this study was to determine if silica dust, an occupational irritant causing inflammation, activates sensory neurons supplying the nasal cavity. Male Fischer 344 rats were placed in inhalation chambers and exposed daily to 2 mg/m3 of fresh silica (average diameter 1 mum) for 6 mo. Following exposure, the trigeminal ganglia (TG) were removed and prepared for SP immunocytochemistry and for preprotachykinin (PPT) autoradiographic in situ hybridization. The SP-like immunofluorescence in TG neurons was subjectively categorized as high, moderate, or low ( background) intensity. In situ hybridization autoradiographs were quantified on the basis of grain density using digital imaging analysis. The SP immunoreactivity and PPT mRNA expression in the TG neurons were significantly increased after silica inhalation. The proportion of highly positive SP-immunoreactive neurons shifted from 1.30 +/- 0.58% in controls to 11.30 +/- 1.15% after silica treatment. The neurons exhibiting high grain density for PPT mRNA increased from 1.50 +/- 0.87% in controls to 11.67 +/- 0.58% in the silica group. Thus, inhalation of silica causes upper airway irritation resulting in increased levels of immunoreactive neuronal SP and PPT mRNA. These findings suggest that silica activates sensory pathways that may be involved in nasal inflammation. [Description provided by NIOSH]
• Subjects:
  Aluminum Silicates Animals Inhalation Exposure Nose Occupational Health Respiratory System Safety Sense Organs Silicon Dioxide
• Keywords:
  Animal-studies Inhalants Inhalation-studies Nasal-cavity Nasal-disorders Silica-dusts Silicates
• ISSN:
  0098-4108
• Document Type:
  Text
• Genre:
  Journal Article
• Place as Subject:
  OSHA Region 3 ; West Virginia
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  HELD - Health Effects Laboratory Division
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Volume:
  53
• Issue:
  8
• NIOSHTIC Number:
  nn:20024991
• Citation:
  J Toxicol Environ Health A 1998 Apr; 53(8):593-605
• Contact Point Address:
  Dr. Richard D. Dey, P.O Box 9128, Morgantown, WV 26505-9128
• Email:
  rdey@wvu.edu
• Federal Fiscal Year:
  1998
• Peer Reviewed:
  True
• Source Full Name:
  Journal of Toxicology and Environmental Health, Part A: Current Issues
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:3a1b940f0d5f8005f6702db46dc82745b768512302b627a92c445aab142862206aaf882239480c0cb93c4f6b9a2bf8070090ce5f1a547cfd8d24640b32067f58
• Download URL:
  https://stacks.cdc.gov/view/cdc/196531/cdc_196531_DS1.pdf
• File Type:
  [PDF - 419.89 KB ]