title: Effects of acute inhalation of aerosols generated during resistance spot welding with mild-steel on pulmonary, vascular and immune responses in rats.
abstract: Spot welding is used in the automotive and aircraft industries, where high-speed, repetitive welding is needed to join thin sections of metal. Epoxy adhesives are applied as sealers to the metal seams. Pulmonary function abnormalities and airway irritation have been reported in spot welders, but no animal toxicology studies exist. Therefore, the goal of this study was to investigate vascular, immune and lung toxicity measures after exposure to these metal fumes in an animal model. Male Sprague-Dawley rats were exposed by inhalation to 25 mg/m³ to either mild-steel spot welding aerosols with sparking (high metal, HM) or without sparking (low metal, LM) for 4 h/d for 3, 8 and 13 d. Shams were exposed to filtered air. Bronchoalveolar lavage (BAL), lung gene expression and ex vivo BAL cell challenge were performed to assess lung toxicity. Lung resistance (R(L)) was evaluated before and after challenge with inhaled methacholine (MCh). Functional assessment of the vascular endothelium in isolated rat tail arteries and leukocyte differentiation in the spleen and lymph nodes via flow cytometry was also done. Immediately after exposure, baseline R(L) was significantly elevated in the LM spot welding aerosols, but returned to control level by 24 h postexposure. Airway reactivity to MCh was unaffected. Lung inflammation and cytotoxicity were mild and transient. Lung epithelial permeability was significantly increased after 3 and 8 d, but not after 13 d of exposure to the HM aerosol. HM aerosols also caused vascular endothelial dysfunction and increased CD4+, CD8+ and B cells in the spleen. Only LM aerosols caused increased IL-6 and MCP-1 levels compared with sham after ex vivo LPS stimulation in BAL macrophages. Acute inhalation of mild-steel spot welding fumes at occupationally relevant concentrations may act as an irritant as evidenced by the increased R(L) and result in endothelial dysfunction, but otherwise had minor effects on the lung.
authors.affiliation: Health Effects Laboratory Division, National Institute for Occupational Safety and Health , Morgantown, WV , USA.
authors.forename: Patti C
authors.initials: PC
authors.lastname: Zeidler-Erdely
authors.forename: Terence G
authors.initials: TG
authors.lastname: Meighan
authors.forename: Aaron
authors.initials: A
authors.lastname: Erdely
authors.forename: Jeffrey S
authors.initials: JS
authors.lastname: Fedan
authors.forename: Janet A
authors.initials: JA
authors.lastname: Thompson
authors.forename: Suzan
authors.initials: S
authors.lastname: Bilgesu
authors.forename: Stacey
authors.initials: S
authors.lastname: Waugh
authors.forename: Stacey
authors.initials: S
authors.lastname: Anderson
authors.forename: Nikki B
authors.initials: NB
authors.lastname: Marshall
authors.forename: Aliakbar
authors.initials: A
authors.lastname: Afshari
authors.forename: Walter
authors.initials: W
authors.lastname: McKinney
authors.forename: David G
authors.initials: DG
authors.lastname: Frazer
authors.forename: James M
authors.initials: JM
authors.lastname: Antonini
mesh_terms: D000269:Adhesives / Q000737:chemistry; D000336:Aerosols; D000395:Air Pollutants, Occupational / Q000633:toxicity*; D000818:Animals; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000276:immunology / Q000503:physiopathology; D005390:Fires; D006411:Hematopoiesis, Extramedullary / Q000187:drug effects; D018928:Immunity, Mucosal / Q000187:drug effects; D019570:Inhalation Exposure / Q000009:adverse effects*; D007962:Leukocytes / Q000187:drug effects / Q000276:immunology / Q000473:pathology; D008168:Lung / Q000098:blood supply / Q000187:drug effects* / Q000276:immunology / Q000473:pathology; D016676:Macrophages, Alveolar / Q000187:drug effects / Q000276:immunology / Q000473:pathology; D008297:Male; D017207:Rats, Sprague-Dawley; D020545:Respiratory Mucosa / Q000187:drug effects* / Q000276:immunology / Q000473:pathology; D013047:Specific Pathogen-Free Organisms; D013154:Spleen / Q000187:drug effects / Q000276:immunology / Q000473:pathology; D013232:Steel / Q000737:chemistry; D023382:Toxicity Tests, Acute; D014657:Vasculitis / Q000139:chemically induced* / Q000276:immunology / Q000473:pathology / Q000503:physiopathology; D014896:Welding / Q000379:methods
chemical_list: D000269:Adhesives; D000336:Aerosols; D000395:Air Pollutants, Occupational; D013232:Steel
keywords: Cardiovascular; inhalation studies; particulate matter; volatile organic compounds; welding