title: Two- and 13-week inhalation toxicities of indium-tin oxide and indium oxide in rats.
abstract: OBJECTIVE
  Two- and 13-week inhalation toxicities of indium-tin oxide (ITO) and indium oxide (IO) were characterized for risk assessments of workers exposed to ITO.
  
  
  METHODS
  F344 rats of both sexes were exposed by inhalation to ITO or IO aerosol for 6 h/day, 5 day/wk for 2 wk at 0, 0.1, 1, 10 or 100 mg/m(3) or 13 wk at 0, 0.1 or 1 mg/m(3). An aerosol generator and inhalation exposure system was constructed.
  
  
  RESULTS
  Blood and lung contents of indium were elevated in a dose-related manner in the ITO- and IO-exposed rats. ITO and IO particles were deposited in the lung, mediastinal lymph node and nasal-associated lymphoid tissue. Exposures to ITO and IO induced alveolar proteinosis, infiltrations of alveolar macrophages and inflammatory cells and alveolar epithelial hyperplasia in addition to increased lung weight. ITO affected the lung more severely than IO did. Fibrosis of alveolar wall developed and some of these lesions worsened at the end of the 26-week post-exposure period.
  
  
  CONCLUSIONS
  Persistent pulmonary lesions including alveolar proteinosis and macrophage infiltration occurred after 2- and 13-week inhalation exposures of rats to ITO and IO. Fibrosis of alveolar wall developed later. These lesions occurred after ITO exposure at the same concentration as the current occupational exposure limit in the USA and at blood indium levels below the biological exposure index in Japan for indium.
authors.affiliation: Japan Bioassay Research Center, Japan Industrial Safety and Health Association.
authors.forename: Kasuke
authors.initials: K
authors.lastname: Nagano
authors.forename: Kaoru
authors.initials: K
authors.lastname: Gotoh
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Kasai
authors.forename: Shigetoshi
authors.initials: S
authors.lastname: Aiso
authors.forename: Tomoshi
authors.initials: T
authors.lastname: Nishizawa
authors.forename: Makoto
authors.initials: M
authors.lastname: Ohnishi
authors.forename: Naoki
authors.initials: N
authors.lastname: Ikawa
authors.forename: Yoko
authors.initials: Y
authors.lastname: Eitaki
authors.forename: Kenichi
authors.initials: K
authors.lastname: Yamada
authors.forename: Heihachiro
authors.initials: H
authors.lastname: Arito
authors.forename: Shoji
authors.initials: S
authors.lastname: Fukushima
mesh_terms: D000280:Administration, Inhalation; D000818:Animals; D005260:Female; D007204:Indium / Q000097:blood / Q000633:toxicity*; D019570:Inhalation Exposure / Q000009:adverse effects*; D016676:Macrophages, Alveolar / Q000187:drug effects / Q000473:pathology*; D008297:Male; D011649:Pulmonary Alveolar Proteinosis / Q000139:chemically induced / Q000473:pathology*; D011658:Pulmonary Fibrosis / Q000139:chemically induced / Q000473:pathology*; D051381:Rats; D011916:Rats, Inbred F344; D013997:Time Factors; D017971:Tin Compounds / Q000097:blood / Q000633:toxicity*
chemical_list: D017971:Tin Compounds; D007204:Indium; C047711:indium oxide; C109984:indium tin oxide