Comparative study on the pulmonary toxicity of indium hydroxide, indium-tin oxide, and indium oxide following intratracheal instillations into the lungs of rats

Akiyo Tanaka, Miyuki Hirata, Nagisa Matsumura, Kazunori Koga, Masaharu Shiratani, Yutaka Kiyohara

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Citation (Scopus)


We studied the pulmonary toxicity of indium hydroxide (In(OH)3), which is produced during a recycling process of indium-tin oxide (ITO), in comparison with that of ITO or indium oxide (In2O3), two raw materials of flat panel displays. One hundred and forty-four male Wistar rats were intratracheally given equivalent doses of 10 mg/kg indium as In(OH)3, ITO, or In2O3particles, twice a week, for a total of 5 times for 2 weeks. Control rats were given distilled water as a vehicle. After 3 weeks, these rats were serially euthanized, and toxicological effects were determined. Body weight gain was significantly suppressed in the In(OH)3-treated rats compared to that in the control group, but not in the ITO-or In2O3-treated rats. Relative lung weights in all the indium-treated groups significantly increased compared to those in the control group throughout the observation period. Furthermore, lung weights in the In(OH)3 group were significantly higher than those in either the ITO or In2O3 group. Blood indium levels in the In(OH)3-treated rats were much higher, 70-to 200-fold, than those in the In2O3- or ITO-treated rats at each time point. Although the lung indium content decreased gradually during the observation periods, the content in the In(OH)3 group was significantly higher than that in either the ITO or In2O3 group. A histopathological analysis revealed foci indicating a slight to severe pulmonary inflammatory response, including exudation to alveolar spaces, were present in all the indium-treated groups. Interstitial fibrotic proliferation was seen only in the In(OH)3-treated rats. The severity of these lesions in the In(OH)3-treated rats was greater than that in either the ITO-or In203-treated rats. The results of our study clearly demonstrated that In(OH)3 particles caused severe pulmonary toxicity when repeated intratracheal instillations were performed in rats. Furthermore, the toxic potency of In(OH)3 in the lung was much higher than that of ITO and In2O3. Accordingly, the toxicity of In(OH)3 particles should be considered in addition to that of ITO and In2O3 particles when indium exposure occurs.

Original languageEnglish
Title of host publicationPlasma Processing and Diagnostics for Life Sciences
EditorsE.R. Fisher, M. Kong, K.D. Weltmann, M. Shiratani
PublisherMaterials Research Society
Number of pages6
ISBN (Electronic)9781510806078
Publication statusPublished - 2015
Event2014 MRS Fall Meeting - Boston, United States
Duration: Nov 30 2014Dec 5 2014

Publication series

NameMaterials Research Society Symposium Proceedings
ISSN (Print)0272-9172


Other2014 MRS Fall Meeting
Country/TerritoryUnited States

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering


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