Intratracheal coexposure to diesel exhaust particulate and crystalline silica in rats potentiates the inflammatory effects of silica in the lungs

Details

• Personal Author:
  Antonini JM ; Chen BT ; Fedan, Jeffery S. ; McLoughlin CE ; Roberts, Jennifer R. ; Schwegler-Berry D ; Yingling BM
• Description:
  Worker exposure to high levels of respirable dust containing crystalline silica and diesel exhaust (DE) has become a concern during hydraulic fracturing operations. The goal of the current study was to investigate the effects of acute pulmonary co-exposures to silica and DE particulate (DEP) in vivo. Doses were derived from field measures using the high point values for respirable silica, applied to a human pulmonary deposition model, and normalized to the surface area of the rat lung. The silica dose of 230 ug/rat represents 2.5 mg/m3 for 12 hr/d for 14 d. The DEP dose of 7.9 ug represents 0.1 mg/m3 for the same duration in a deposition model for total carbon (TC). A 50 ug dose of DEP was also used to represent approximately 0.6 mg/ m3 TC for the same duration. Rats were exposed by a single intratracheal instillation of sterile PBS as vehicle or one of the following doses: 7.9 ug DEP, 50 ug DEP, 230 ug silica, or silica and DEP combined for each dose of DEP. At 1 d, 1 wk, and 1 mo post-exposure, bronchoalveolar lavage (BAL) was performed on the right lungs; cells and fluid were retained to assess pulmonary injury and inflammation. Lung-associated lymph nodes (LALN) were harvested to evaluate immune responses. Silica alone caused increased inflammation and lung injury at all times post-exposure, indicated by increased neutrophil influx, oxidant production, and lactate dehydrogenase (LDH) in BAL. DEP alone caused only slight inflammation 1 d post-exposure but no effects later. At 1 wk and 1 mo after exposure, 50 ug DEP significantly increased the inflammatory effects of silica. In addition, at 1 mo, both co-exposure doses significantly enhanced the phagocyte oxidant production over silica alone. Lymphocyte counts in LALN in the co-exposures were not elevated relative to silica exposure alone. In summary, DEP alone produced relatively no pulmonary toxicity; however, DEP in a co-exposure with silica has the capability to potentiate the adverse effects of silica in the lung. [Description provided by NIOSH]
• Subjects:
  Aerosols Air Pollutants, Occupational Air Pollution Air Pollution, Indoor Aluminum Silicates Animals Chemistry Dust Environmental Exposure Environmental Pollution Irritants Laboratories Lung Occupational Health Particulate Matter Respiratory System Respiratory Tract Diseases Safety Silicon Dioxide Toxicology Vehicle Emissions Workplace

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• Keywords:
  Air-quality Chemical-composition Diesel-emissions Diesel-exhausts Dust-exposure Dust-particles Dusts Environmental-pollution Exposure-levels Fumes Hydraulic-equipment In-vivo-study Laboratory-animals Particulates Pollutants Pollution Pulmonary-function Pulmonary-system Pulmonary-system-disorders Respiration Respiratory-irritants Respiratory-system-disorders Silica-dusts Silicates Work-environment Workers

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• ISSN:
  1096-6080
• Document Type:
  Text
• Genre:
  Abstract or Summary
• 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:
  138
• Issue:
  1
• NIOSHTIC Number:
  nn:20043919
• Citation:
  Toxicologist 2014 Mar; 138(1):329
• CAS Registry Number:
  Quartz (SiO2) (CAS RN 14808-60-7) ; Silica (CAS RN 7631-86-9)
• Federal Fiscal Year:
  2014
• NORA Priority Area:
  Manufacturing
• Peer Reviewed:
  False
• Source Full Name:
  The Toxicologist. Society of Toxicology 53rd Annual Meeting and ToxExpo, March 23-27, 2014, Phonex, Arizona
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:a88307aedc645354761c984b32b5d66c2f82c233e71590824f3d381ed14c0ada469ae385ed3f61dc4fb8f79bef7af29caf65236edcf06ff305683325e3807e17
• Download URL:
  https://stacks.cdc.gov/view/cdc/199788/cdc_199788_DS1.pdf
• File Type:
  [PDF - 237.24 KB ]