Pulmonary Toxicity of Expancel® Microspheres in the Rat

Details

• Personal Author:
  Andrew, Michael E. ; Baron, Paul A. ; Battelli MA ; Beighley CM ; Castranova, Vincent ; Hubbs, Ann F. ; Millecchia LL ; Porter DW ; Schwegler-Berry DE ; Wolfarth MG
• Description:
  Expancel microspheres are thermoplastic microspheres enclosing hydrocarbon. These microspheres expand when heated, producing many applications. Because they have unknown biological persistence and toxicity, we investigated the toxicity of two unexpanded (11.1 and 15.4 m mean diameter) and two expanded (3.1 and 5.5 m mass median aerodynamic diameter) Expancel microspheres in intratracheally-instilled, male, Sprague-Dawley rats. Pulmonary histopathology was evaluated at 28 days postexposure. Bronchoalveolar lavage fluid was evaluated at days 1, 7, 14, and 28 days postexposure. Crystalline silica was the positive control. By histopathology, both unexpanded and expanded microspheres caused granulomatous bronchopneumonia characterized by macrophages and giants cells, suggesting a persistent foreign body response. Expanded, but not unexpanded microspheres, also caused eosinophilic bronchitis and bronchiolitis, mucous metaplasia of airways and organized granulomatous inflammation with associated fibrosis and frequent airway obstruction. In contrast, alveolar macrophage activation, polymorphonuclear leukocytes, LDH and albumin in bronchoalveolar laveage fluid were initially elevated but returned to near control levels at 28 days, and did not reflect the persistent granulomatous bronchopneumonia caused by Expancel microspheres. These findings emphasize the importance of histopathology for evaluating pulmonary toxicity, suggest that Expancel microspheres are a potential occupational hazard, and indicate a need for additional studies on their potential pulmonary toxicity. [Description provided by NIOSH]
• Subjects:
  Animals Laboratories Lung Occupational Health Respiratory System Respiratory Tract Diseases Safety Silicon Dioxide Toxicology
• Keywords:
  Animal-studies Dose-response Exposure-levels Histopathology Laboratory-animals Lung-function Occupational-respiratory-disease Pulmonary-system-disorders Respiratory-system-disorders Silica-dusts Toxicopathology

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• ISSN:
  0192-6233
• Document Type:
  Text
• Genre:
  Journal Article
• 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 ; DART - Division of Applied Research and Technology
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Volume:
  35
• Issue:
  5
• NIOSHTIC Number:
  nn:20032595
• Citation:
  Toxicol Pathol 2007 Aug; 35(5):702-714
• Contact Point Address:
  National Institute for Occupational Safety and Health, Health Effects Laboratory Division, Mail Stop 2015, 1095 Willowdale Road, Morgantown, WV 26505
• Email:
  DPorter@cdc.gov
• CAS Registry Number:
  Quartz (SiO2) (CAS RN 14808-60-7) ; Silica (CAS RN 7631-86-9)
• Federal Fiscal Year:
  2007
• NORA Priority Area:
  Manufacturing
• Peer Reviewed:
  True
• Source Full Name:
  Toxicologic Pathology
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:0153c929bd78baf61aabd5f887ee670cb6787795916d8e247d2a0814687dbb8a72db8163bfa72b7989216f76c158fbe5b3e6f3b5081ca5d610b2242f320dc74d
• Download URL:
  https://stacks.cdc.gov/view/cdc/186511/cdc_186511_DS1.pdf
• File Type:
  [PDF - 6.31 MB ]