Potential Role of Silicon-Oxygen Radicals in Acute Lung Injury

Details

• Personal Author:
  Dalal NS ; Shi X ; Vallyathan V
• Description:
  Occupational exposure to silica is associated with the development of acute and chronic silicosis. Chronic silicosis usually becomes manifest 20-40 years after first exposure and is characterized by the development of typical nodular lesions over a period of several decades. Acute silicosis, on the other hand, occurs much less commonly. It is manifested by a rapid onset following exposure and is characterized by a lipoproteinaceous exudate within air spaces. All the reported studies on the pathogenesis of silicosis have been focused on the elucidation of cellular mechanism leading to cell injury and the development of chronic silicosis. Since pulmonary responses to silica differ in the presentation of acute and chronic silicosis, we hypothesized the acute response is associated with some unique properties of dust generated by shearing or grinding as in sandblasting, drilling, tunnelling or mill operations. To test this hypothesis, we mechanically ground silica and measured Si-0 radicals concentration using electron spin spectroscopy. We also studied the generation of OH from Si-0 radicals in biologic buffers and showed the biologic reactivity of freshly ground silica is enhanced substantially compared to aged silica by a greater respiratory burst, increased secretions of superoxide anion, hydrogen peroxide and nitro blue tetrazolium reduction. In addition, the freshly ground silica also induced a greater cytotoxicity by an enhanced ability for lipid peroxidation, greater release of lactate dehydrogenase from alveolar macrophages, and increased lysis of sheep erythrocytes. The results of these studies suggest that freshly fractured silica containing Si-0 radicals leads to the generation of OH radicals which may play a central role in cell membrane damage by the initiation of lipid peroxidation leading to acute silicosis. [Description provided by NIOSH]
• Subjects:
  Cytotoxins Dust Free Radicals Lung Occupational Health Quartz Respiratory System Safety Silicon Dioxide
• Keywords:
  Biological Effects Cytotoxic Effects Free Radicals Lung Irritants Mineral Dusts Pulmonary Effects Quartz Dust Respirable Dust Silica Silicosis
• Publisher:
  N.A.T.O. (North Atlantic Treaty Organization)
• 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:
  DRDS - Division of Respiratory Disease Studies
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  35
• NIOSHTIC Number:
  nn:20059125
• Citation:
  Fourth International Workshop on Effects of Mineral Dusts on Cells, September 21-23, 1988, Orford, Quebec, Canada. Brussels, Belgium: N.A.T.O. (North Atlantic Treaty Organization), 1988 Sep; :35
• CAS Registry Number:
  Quartz (SiO2) (CAS RN 14808-60-7)
• Federal Fiscal Year:
  1988
• Peer Reviewed:
  False
• Source Full Name:
  Fourth International Workshop on Effects of Mineral Dusts on Cells, September 21-23, 1988, Orford, Quebec, Canada
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:bd4b0c38d5edd525377d4934d2853b462936b5b3c72bb334e56c796d50ea23924974d400abc1cffbf3fcbfff5f6a5c4a309d219183de9aab1182976d3571abc2
• Download URL:
  https://stacks.cdc.gov/view/cdc/223438/cdc_223438_DS1.pdf
• File Type:
  [PDF - 718.44 KB ]