Direct and Indirect Effects of Single Walled Carbon Nanotubes on RAW 264.7 Macrophages: Role of Iron

Details

• Personal Author:
  Castranova, Vincent ; Kagan VE ; Kisin ER ; Konduru NV ; Mercer R ; Osipov AN ; Potapovich AI ; Schwegler-Berry D ; Shvedova AA ; Tyurin VA ; Tyurina YY
• Description:
  Single-walled carbon nanotubes (SWCNT), nano-cylinders with an extremely small diameter (1-2 nm) and high aspect ratio, have unique physico-chemical, electronic and mechanical properties and may exhibit unusual interactions with cells and tissues, thus necessitating studies of their toxicity and health effects. Manufactured SWCNT usually contain significant amounts of iron that may act as a catalyst of oxidative stress. Because macrophages are the primary responders to different particles that initiate and propagate inflammatory reactions and oxidative stress, we utilized two types of SWCNT: (1) iron-rich (non-purified) SWCNT (26 wt.% of iron) and (2) iron-stripped (purified) SWCNT (0.23 wt.% of iron) to study their interactions with RAW 264.7 macrophages. Ultrasonication resulted in predominantly well-dispersed and separated SWCNT strands as evidenced by scanning electron microscopy. Neither purified nor non-purified SWCNT were able to generate intracellular production of superoxide radicals or nitric oxide in RAW 264.7 macrophages as documented by flow-cytometry and fluorescence microscopy. SWCNT with different iron content displayed different redox activity in a cell-free model system as revealed by EPR-detectable formation of ascorbate radicals resulting from ascorbate oxidation. In the presence of zymosan-stimulated RAW 264.7 macrophages, non-purified iron-rich SWCNT were more effective in generating hydroxyl radicals (documented by EPR spin-trapping with 5,5-dimethyl-1-pyrroline-N-oxide, DMPO) than purified SWCNT. Similarly, EPR spin-trapping experiments in the presence of zymosan-stimulated RAW 264.7 macrophages showed that non-purified SWCNT more effectively converted superoxide radicals generated by xanthine oxidase/xanthine into hydroxyl radicals as compared to purified SWCNT. Iron-rich SWCNT caused significant loss of intracellular low molecular weight thiols (GSH) and accumulation of lipid hydroperoxides in both zymosan-and PMA-stimulated RAW 264.7 macrophages. Catalase was able to partially protect macrophages against SWCNT induced elevation of biomarkers of oxidative stress (enhancement of lipid peroxidation and GSH depletion). Thus, the presence of iron in SWCNT may be important in determining redox-dependent responses of macrophages. [Description provided by NIOSH]
• Subjects:
  Ferrous Compounds Occupational Health Safety
• Keywords:
  Iron-compounds Microscopy Nanotechnology Oxidation Oxidative-processes Oxides
• ISSN:
  0378-4274
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Journal Article
• Place as Subject:
  OSHA Region 3 ; Pennsylvania ; West Virginia
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  HELD - Health Effects Laboratory Division
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  88-100
• Volume:
  165
• Issue:
  1
• NIOSHTIC Number:
  nn:20030624
• Citation:
  Toxicol Lett 2006 Aug; 165(1):88-100
• Contact Point Address:
  Center for Free Radical and Antioxidant Health, Department of EOH, Bridgeside Point, 100 Technology Drive, Suite 350, Pittsburgh, PA 15219, United States
• Email:
  vkagan@eoh.pitt.edu
• CAS Registry Number:
  Iron (CAS RN 7439-89-6)
• Federal Fiscal Year:
  2006
• NORA Priority Area:
  Disease and Injury: Asthma and Chronic Obstructive Pulmonary Disease
• Performing Organization:
  University of Pittsburgh at Pittsburgh
• Peer Reviewed:
  True
• Start Date:
  20050701
• Source Full Name:
  Toxicology Letters
• End Date:
  20160630
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:78bb68cecdf87ee06f204459ad0f43bce438628386baff60c5b903ced4f48b1c8423c1a6a23a97184d67c3647b4537d1f54ff1fef871febf3b7eba60437d0a04
• Download URL:
  https://stacks.cdc.gov/view/cdc/191169/cdc_191169_DS1.pdf
• File Type:
  [PDF - 574.38 KB ]