title: Inhalation carcinogenicity and chronic toxicity of indium-tin oxide in rats and mice.
abstract: OBJECTIVE
  Carcinogenicity and chronic toxicity of indium-tin oxide (ITO) were examined by inhalation exposure of rats and mice to ITO aerosol.
  
  
  METHODS
  Fifty mice of both sexes were exposed to ITO at 0 (control), 0.01, 0.03 or 0.1 mg/m(3) for 6 h/day, 5 day/wk for 104 wk, and 50 rats of both sexes were exposed to 0, 0.01 or 0.03 mg/m(3) ITO for the same time period. The repeated exposure of 50 rats of both sexes to 0.1 mg/m(3) ITO was discontinued at the 26th wk, followed by clean air exposure for the remaining 78 wk.
  
  
  RESULTS
  In rats, incidences of bronchiolo-alveolar adenomas and carcinomas, bronchiolo-alveolar hyperplasia, alveolar wall fibrosis and thickened pleural wall, alveolar proteinosis and infiltrations of alveolar macrophages and inflammatory cells were significantly increased. Combined incidences of malignant lung tumors in male rats and total lung tumors in male and female rats were significantly increased at exposure to 0.01 mg/m(3) ITO. In mice, no carcinogenic response occurred, but thickened pleural wall, alveolar proteinosis and alveolar macrophage infiltration were induced. Mice were less susceptible to ITO than rats. The lung content of indium was the greatest, followed by the spleen, kidney and liver. Blood indium levels increased dose-dependently.
  
  
  CONCLUSIONS
  There was clear evidence of carcinogenicity of inhaled ITO in male and female rats but not clear evidence in mice, together with occurrence of the chronic pulmonary lesions in both rats and mice.
authors.affiliation: Japan Bioassay Research Center, Japan Industrial Safety and Health Association, Japan.
authors.forename: Kasuke
authors.initials: K
authors.lastname: Nagano
authors.forename: Tomoshi
authors.initials: T
authors.lastname: Nishizawa
authors.forename: Yumi
authors.initials: Y
authors.lastname: Umeda
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Kasai
authors.forename: Tadashi
authors.initials: T
authors.lastname: Noguchi
authors.forename: Kaoru
authors.initials: K
authors.lastname: Gotoh
authors.forename: Naoki
authors.initials: N
authors.lastname: Ikawa
authors.forename: Yoko
authors.initials: Y
authors.lastname: Eitaki
authors.forename: Yaeko
authors.initials: Y
authors.lastname: Kawasumi
authors.forename: Tsuneyuki
authors.initials: T
authors.lastname: Yamauchi
authors.forename: Heihachiro
authors.initials: H
authors.lastname: Arito
authors.forename: Shoji
authors.initials: S
authors.lastname: Fukushima
mesh_terms: D002282:Adenocarcinoma, Bronchiolo-Alveolar / Q000139:chemically induced / Q000453:epidemiology; D000236:Adenoma / Q000139:chemically induced / Q000453:epidemiology; D000336:Aerosols; D000818:Animals; D015197:Carcinogenicity Tests; D005260:Female; D019570:Inhalation Exposure / Q000009:adverse effects; D008168:Lung / Q000187:drug effects* / Q000473:pathology*; D008175:Lung Neoplasms / Q000139:chemically induced* / Q000453:epidemiology*; D008297:Male; D051379:Mice; D051381:Rats; D011916:Rats, Inbred F344; D016019:Survival Analysis; D017971:Tin Compounds / Q000097:blood / Q000633:toxicity* / Q000652:urine
chemical_list: D000336:Aerosols; D017971:Tin Compounds; C109984:indium tin oxide