Mild Steel Welding Fume Causes Manganese Accumulation and Subtle Neuroinflammatory Changes but Not Overt Neuronal Damage in Discrete Brain Regions of Rats After Short-Term Inhalation Exposure

Details

• Personal Author:
  Antonini JM ; Benkovic SA ; Billig BK ; Chen BT ; Felton CM ; Frazer DG ; Hammer MA ; Jefferson AM ; Ma F ; Miller DB ; O'Callaghan JP ; Roberts, Jennifer R. ; Schwegler-Berry D ; Sriram K ; Stone S
• Description:
  Serious questions have been raised by occupational health investigators regarding a possible causal association between neurological effects in welders and the presence of manganese (Mn) in welding fume. Male Sprague-Dawley rats were exposed by inhalation to 40 mg/m3 of gas metal arc-mild steel (MS) welding fume for 3 h/day for 10 days. Generated fume was collected in the animal chamber during exposure, and particle size, composition, and morphology were characterized. At 1 day after the last exposure,metal deposition in different organ systems and neurological responses in dopaminergic brain regions were assessed in exposed animals. The welding particles were composed primarily of a complex of iron (Fe) and Mn and were arranged as chain-like aggregates with a significant number of particles in the nanometer size range. Mnwas observed to translocate from the lungs to the kidney and specific brain regions (olfactory bulb, cortex, and cerebellum) after MS fume inhalation. In terms of neurological responses, short-term MS fume inhalation induced significant elevations in divalent metal ion transporter 1 (Dmt1) expression in striatum and midbrain and significant increases in expression of proinflammatory chemokines (Ccl2, Cxcl2) and cytokines (IL1b, TNFa) in striatum. In addition, mRNA and protein expression of glial fibrillary acidic protein (GFAP) was significantly increased in striatum after MS fume exposure. However, the 10-day MS welding fume inhalation did not cause any changes in dopamine and its metabolites or GABA in dopaminergic brain regions nor did it produce overt neural cell damage as assessed by histopathology. In summary, short-term MS welding fume exposure led to translocation of Mn to specific brain regions and induced subtle changes in cell markers of neuroinflammatory and astrogliosis. The neurofunctional significance of these findings currently is being investigated in longer, more chronic welding fume exposure studies. [Description provided by NIOSH]
• Subjects:
  Air Pollutants, Occupational Environmental Monitoring Hypersensitivity Laboratories Manganese Nervous System Nervous System Disorders Occupational Health Particulate Matter Respiratory System Safety Welding

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• Keywords:
  Airborne-particles Author Keywords: Welding Fume Cell-biology Cell-damage Cellular-reactions Central-nervous-system-disorders Chemical-hypersensitivity Dopaminergic Neurotoxicity Exposure-assessment Exposure-levels Exposure-methods Fumes Gliosis Inhalation Inhalation-studies Laboratory-animals Laboratory-testing Manganism Neuroinflammation Neurological-reactions Neurological-system Neurotoxic-effects Welding-industry

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• ISSN:
  0161-813X
• Document Type:
  Text
• Genre:
  Journal Article
• 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:
  30
• Issue:
  6
• NIOSHTIC Number:
  nn:20036211
• Citation:
  Neurotoxicology 2009 Nov; 30(6):915-925
• Contact Point Address:
  James M. Antonini, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, 1095 Willowdale Road, Mailstop 2015, Morgantown, WV 26505
• Email:
  jga6@cdc.gov
• CAS Registry Number:
  Magnesium (CAS RN 7439-95-4)
• Federal Fiscal Year:
  2010
• NORA Priority Area:
  Construction ; Manufacturing
• Peer Reviewed:
  True
• Source Full Name:
  Neurotoxicology
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:7f0025e89128dc90f03415537338517e2fa56d91d6f760602eded6164a229b1234dd7fc2e58b92d7a37d1147d9e3b34f7bc37a0064d2d1e14491e82386e3b3f5
• Download URL:
  https://stacks.cdc.gov/view/cdc/187726/cdc_187726_DS1.pdf
• File Type:
  [PDF - 589.33 KB ]