Re-evaluation of pulmonary titanium dioxide nanoparticle distribution using the "relative deposition index": Evidence for clearance through microvasculature

Mühlfeld, Christian; Geiser, Marianne; Kapp, Nadine; Gehr, Peter; Rothen-Rutishauser, Barbara (2007). Re-evaluation of pulmonary titanium dioxide nanoparticle distribution using the "relative deposition index": Evidence for clearance through microvasculature. Particle and fibre toxicology, 4, p. 7. London: BioMed Central 10.1186/1743-8977-4-7

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ABSTRACT: BACKGROUND: Translocation of nanoparticles (NP) from the pulmonary airways into other pulmonary compartments or the systemic circulation is controversially discussed in the literature. In a previous study it was shown that titanium dioxide (TiO2) NP were "distributed in four lung compartments (air-filled spaces, epithelium/endothelium, connective tissue, capillary lumen) in correlation with compartment size". It was concluded that particles can move freely between these tissue compartments. To analyze whether the distribution of TiO2 NP in the lungs is really random or shows a preferential targeting we applied a newly developed method for comparing NP distributions. METHODS: Rat lungs exposed to an aerosol containing TiO2 NP were prepared for light and electron microscopy at 1 h and at 24 h after exposure. Numbers of TiO2 NP associated with each compartment were counted using energy filtering transmission electron microscopy. Compartment size was estimated by unbiased stereology from systematically sampled light micrographs. Numbers of particles were related to compartment size using a relative deposition index and chi-squared analysis. RESULTS: Nanoparticle distribution within the four compartments was not random at 1 h or at 24 h after exposure. At 1 h the connective tissue was the preferential target of the particles. At 24 h the NP were preferentially located in the capillary lumen. CONCLUSION: We conclude that TiO2 NP do not move freely between pulmonary tissue compartments, although they can pass from one compartment to another with relative ease. The residence time of NP in each tissue compartment of the respiratory system depends on the compartment and the time after exposure. It is suggested that a small fraction of TiO2 NP are rapidly transported from the airway lumen to the connective tissue and subsequently released into the systemic circulation.

Item Type:

Journal Article (Original Article)

Division/Institute:

04 Faculty of Medicine > Pre-clinic Human Medicine > Institute of Anatomy > Topographical and Clinical Anatomy
04 Faculty of Medicine > Pre-clinic Human Medicine > Institute of Anatomy > Cell Biology
04 Faculty of Medicine > Pre-clinic Human Medicine > Institute of Anatomy
04 Faculty of Medicine > Pre-clinic Human Medicine > BioMedical Research (DBMR) > Forschungsbereich Mu50 > Forschungsgruppe Pneumologie (Erwachsene)

UniBE Contributor:

Mühlfeld, Christian; Geiser, Marianne; Kapp, Nadine; Gehr, Peter and Rothen-Rutishauser, Barbara

ISSN:

1743-8977

ISBN:

17727712

Publisher:

BioMed Central

Language:

English

Submitter:

Factscience Import

Date Deposited:

04 Oct 2013 14:55

Last Modified:

06 Dec 2014 21:29

Publisher DOI:

10.1186/1743-8977-4-7

PubMed ID:

17727712

BORIS DOI:

10.7892/boris.23516

URI:

https://boris.unibe.ch/id/eprint/23516 (FactScience: 42176)

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