Lung Inflammation and Damage After Silica Inhalation in Rats: Is There Recovery?

Details

• Personal Author:
  Castranova, Vincent ; Khan A ; McLaurin JL ; Mercer RR ; Porter DW ; Ramsey D ; Robinson VA ; Teass A
• Description:
  Crystalline silica (quartz) is a well established lung inflammatory and fibrogenic occupational dust. Although the pulmonary effects of silica exposure in animal models has been well studied, the relationships between silica exposure and clearance (recovery) on lung inflammation and damage has not been investigated. To investigate these relationships, rats were exposed to filtered air (control) or 15 mg/m3 silica aerosol (6 hours/day, 5 days/week). Rats were exposed for 20, 40, or 60 days and each exposure group had a corresponding exposure plus 36 day recovery group. Rat lungs were lavaged to isolate bronchoalveolar lavage (BAL) cells and acellular BAL fluid, while samples of whole blood were collected to monitor peripheral leukocytes. Pulmonary inflammation was monitored by measuring BAL polymorphonuclear leukocytes (PMN). BAL PMN cell counts were elevated in silica-exposed versus control rats, and PMN counts increased further during recovery. Blood leukocyte counts displayed a pattern similar to the BAL PMN counts. Silica cytotoxicity was measured by analyses of BAL fluid lactate dehydrogenase (LDH) activity and albumin (ALB) concentration. BAL fluid LDH activities and ALB concentrations were higher in silica-exposed versus control rats, and these parameters continued to increase during recovery. These data indicate that progressively severe silica-induced lung inflammation and damage occurs in response to the duration of silica inhalation and these processes continue after silica exposure has ended. [Description provided by NIOSH]
• Subjects:
  Aerosols Aluminum Silicates Animals Dust Fibrosis Laboratories Lung Lung Diseases Occupational Exposure Occupational Health Quartz Respiratory System Respiratory Tract Diseases Safety Silicon Dioxide

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• Keywords:
  Animal Studies Dust Inhalation Dusts Fibrogenesis Fibrogenicity Fibrous Dusts Inhalation Studies Laboratory Animals Lung Disorders Occupational Exposure Pulmonary System Disorders Quartz Dust Respiratory System Disorders Silica Dusts Silicates

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• ISSN:
  1096-6080
• Document Type:
  Text
• Genre:
  Abstract or Summary
• Place as Subject:
  Ohio ; OSHA Region 3 ; OSHA Region 5 ; West Virginia
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  HELD - Health Effects Laboratory Division ; DBBS - Division of Biomedical and Behavioral Sciences
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Volume:
  54
• Issue:
  1
• NIOSHTIC Number:
  nn:20021035
• Citation:
  Toxicologist 2000 Mar; 54(1):318
• CAS Registry Number:
  Quartz (SiO2) (CAS RN 14808-60-7)
• Federal Fiscal Year:
  2000
• Peer Reviewed:
  False
• Source Full Name:
  The Toxicologist. Society of Toxicology 39th Annual Meeting, March 19-23, 2000, Philadelphia, Pennsylvania
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:1d04dd85d157c900f2c568e5ba95c92b2ccbc26e0f337af3f5a31f5b8f38393f92efc1e070f3a8503c4f1d652dfdb24630dd6fe4cd55004e30a5aa171d7ddd05
• Download URL:
  https://stacks.cdc.gov/view/cdc/198615/cdc_198615_DS1.pdf
• File Type:
  [PDF - 223.83 KB ]