Distribution, elimination, and biopersistence to 90 days of a systemically introduced 30 nm ceria-engineered nanomaterial in rats

Robert A. Yokel, Tu C. Au, Robert MacPhail, Sarita S. Hardas, D. Allan Butterfield, Rukhsana Sultana, Michael Goodman, Michael T. Tseng, Mo Dan, Hamed Haghnazar, Jason M. Unrine, Uschi M. Graham, Peng Wu, Eric A. Grulke

Research output: Contribution to journalArticlepeer-review

116 Scopus citations


Nanoceria is used as a catalyst in diesel fuel, as an abrasive in printed circuit manufacture, and is being pursued as an antioxidant therapeutic. Our objective is to extend previous findings showing that there were no reductions of cerium in organs of the mononuclear phagocyte (reticuloendothelial) system up to 30 days after a single nanoscale ceria administration. An ~5% aqueous dispersion of citrate-stabilized 30 nm ceria, synthesized and characterized in-house, or vehicle, was iv infused into rats terminated 1, 7, 30, or 90 days later. Cageside observations were obtained daily, body weight weekly. Daily urinary and fecal cerium outputs were quantified for 2 weeks. Nine organs were weighed and samples collected from 14 tissues/organs/systems, blood and cerebrospinal fluid for cerium determination. Histology and oxidative stress were assessed. Less than 1% of the nanoceria was excreted in the first 2 weeks, 98% in feces. Body weight gain was initially impaired. Spleen weight was significantly increased in some ceria-treated groups, associated with abnormalities. Ceria was primarily retained in the spleen, liver, and bone marrow. There was little decrease of ceria in any tissue over the 90 days. Granulomas were observed in the liver. Time-dependent oxidative stress changes were seen in the liver and spleen. Nanoscale ceria was persistently retained by organs of the mononuclear phagocyte system, associated with adverse changes. The results support concern about the long-term fate and adverse effects of inert nanoscale metal oxides that distribute throughout the body, are persistently retained, and produce adverse changes.

Original languageEnglish
Pages (from-to)256-268
Number of pages13
JournalToxicological Sciences
Issue number1
StatePublished - May 2012

Bibliographical note

Funding Information:
This work was supported by United States Environmental Protection Agency Science to Achieve Results (grant number RD-833772). Although the research described in this article has been funded wholly or in part by the United States Environmental Protection Agency through STAR Grant RD-833772, it has not been subjected to the Agency’s required peer and policy review and therefore does not necessarily reflect the views of the Agency and no official endorsement should be inferred. Support was provided to T.C.A. (Summer Undergraduate Research Program) from The Pharmaceutical Sciences Department and Office of the Dean, College of Pharmacy, University of Kentucky.


  • Ceria
  • Excretion
  • Rat
  • Retention
  • Tissue distribution

ASJC Scopus subject areas

  • Toxicology


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