Lung deposition and extrapulmonary translocation of nano-ceria after intratracheal instillation.
The broad potential applications of manufactured nanomaterials call for urgent assessment of their environmental and biological safety. However, most of the previous work focused on the cell level performance; little was known about the consequences of nanomaterial exposure at the whole-body and organ levels. In the present paper, the radiotracer technique was employed to study the pulmonary deposition and the translocation to secondary target organs after ceria nanoparticles (nano-ceria) were intratracheally instilled into Wistar rats. It was found that 63.9 +/- 8.2% of the instilled nano-ceria remained in the lung by 28 d postexposure and the elimination half-life was 103 d. At the end of the test period, only 1/8-1/3 of the daily elimination of nano-ceria from the lung was cleared via the gastrointestinal tract, suggesting that phagocytosis by alveolar macrophages (AMs) with subsequent removal towards the larynx was no longer the predominant route for the elimination of nano-ceria from the lung. The whole-body redistribution of nano-ceria demonstrated that the deposited nano-ceria could penetrate through the alveolar wall into the systemic circulation and accumulate in the extrapulmonary organs. In vitro study suggested that nano-ceria would agglomerate and form sediments in the bronchoalveolar aqueous surrounding while binding to protein would be conducive to the redispersion of nano-ceria. The decrease in the size of agglomerates might enhance the penetration of nano-ceria into the systemic circulation. Our findings suggested that the effect of nanomaterial exposure, even at low concentration, should be assessed because of the potential lung and systemic cumulative toxicity of the nanomaterials.
He
Xiao
X
CAS Key Lab for Biomedical Effects of Nanomaterials and Nanosafety, CAS Key Laboratory of Nuclear Analytical Techniques, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, People's Republic of China. hx421@ihep.ac.cn
Zhang
Haifeng
H
Ma
Yuhui
Y
Bai
Wei
W
Zhang
Zhiyong
Z
Lu
Kai
K
Ding
Yayun
Y
Zhao
Yuliang
Y
Chai
Zhifang
Z
D000818:Animals; D001692:Biological Transport; D002563:Cerium / Q000097:blood / Q000737:chemistry / Q000493:pharmacokinetics*; D004333:Drug Administration Routes; D005243:Feces / Q000737:chemistry; D008168:Lung / Q000378:metabolism*; D008297:Male; D053758:Nanoparticles / Q000032:analysis* / Q000737:chemistry / Q000648:ultrastructure; D010316:Particle Size; D051381:Rats; D017208:Rats, Wistar; D014018:Tissue Distribution; D014132:Trachea / Q000378:metabolism*
D002563:Cerium