Inhaled Silica Dust Increases Nitric Oxide and Cytokine Production Associated with Collagen Synthesis and Fibrosis in Rats

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• Personal Author:
  Blackford JA Jr. ; Castranova, Vincent ; Dey RD ; Durham J ; Harness J ; Hubbs A ; Stanley C
• Description:
  Pulmonary responses in the rat to the inhalation of occupationally applicable levels of silica (14808607) were studied. Specific pathogen free male Fischer-rats were exposed to 2.0mg/m3 silica for 8 hours/day, 5 days per week, for periods of 2 weeks, 2 months, or 6 months. Bronchoalveolar lavage cells were extracted and analyzed for cellular differentials, chemiluminescence, platelet derived growth factor (PDGF), transforming growth factor beta (TGFbeta), and messenger RNA (mRNA) levels of inducible nitric-oxide (NO) synthase (iNOS). Northern analysis revealed mRNA levels for iNOS to be increased after 2 months, but returned to normal at 6 months. An increase in red blood cells and leukocytes revealed pulmonary damage and inflammation after 2 and 6 months of exposure. An increase in total and NO dependent chemiluminescence revealed that oxygen radicals and NO were produced by bronchoalveolar lavage cells after 2 and 6 months. Multiple granulomatous lesions and an increase in collagen synthesis were observed after 6 months, and TGFbeta mRNA levels were also elevated after 6 months; however, PDGF mRNA remained comparable to controls. The authors conclude that the inhalation of silica at concentrations that could occur in the mining and sandblasting industry may present a health concern due to this study's findings that significant pulmonary inflammation and fibrosis occur in rats exposed to occupationally relevant levels of silica. [Description provided by NIOSH]
• Subjects:
  Dust Immune System Laboratories Lung Occupational Exposure Occupational Health Respiratory System Safety Silicon Dioxide
• Keywords:
  Alveolar-cells Dust-inhalation Histopathology Immune-reaction Inhalation-studies Laboratory-animals Lung-fibrosis Lung-function NIOSH-Author Occupational-exposure Pulmonary-function Silica-dusts

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• ISSN:
  1047-322X
• Document Type:
  Text
• Genre:
  Journal Article
• Place as Subject:
  Maine ; OSHA Region 1 ; 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:
  11
• Issue:
  7
• NIOSHTIC Number:
  nn:00235404
• Citation:
  Appl Occup Environ Hyg 1996 Jul; 11(7):914-918
• CAS Registry Number:
  Quartz (SiO2) (CAS RN 14808-60-7)
• Federal Fiscal Year:
  1996
• Peer Reviewed:
  True
• Source Full Name:
  Applied Occupational and Environmental Hygiene
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:c1c8de4c9cabacc40390a3288d96babf1c9d0e5801ad1587810848e2ef68e8c92f6794c7c8ecce760efb86fb3115a515eaac95c2a6ecee301b1b0cd270c0a072
• Download URL:
  https://stacks.cdc.gov/view/cdc/197771/cdc_197771_DS1.pdf
• File Type:
  [PDF - 1.08 MB ]