title: Tissue distribution of 20 nm, 100 nm and 1000 nm fluorescent polystyrene latex nanospheres following acute systemic or acute and repeat airway exposure in the rat.
abstract: Understanding tissue distribution and clearance of nanomaterials following different routes of exposure is needed for risk assessment. F344 female rats received single or multiple exposures to 20 nm, 100 nm or 1000 nm latex fluorospheres by intravenous (i.v.) injection or oral pharyngeal aspiration into the airways. The presence of fluorospheres in tissues was assessed up to 90-120 days after the final dose. Blood, perfusion fluid, bone marrow, brain, eyes, feces, gut, heart, kidney, liver, lung, muscle, skin, spleen, thymus, tongue, urine and uterus plus ovaries were collected for analysis. Liver, spleen and lung were the greatest tissue depots for all particles following i.v. injection. The proportion of 100 nm and 1000 nm but not 20 nm spheres significantly increased in the spleen over time. Lung was the greatest tissue depot for all particles following single or repeat airway exposure. Greater than 95% of 1000 nm spheres that were recovered were in the lung in contrast to 70-80% of 20 nm spheres or 89-95% of 100 nm spheres. All 3 sizes were found in gut or gut+feces 1-7 days after lung exposure. The thymus was the largest extra-pulmonary depot for the particles; up to 25% of recovered 20 nm particles were in the thymus up to 4 months after exposure compared to 6% of 100 nm particles and 1-3% of 1000 nm particles. A small proportion of 20 nm particles were detected in kidney following both acute and repeat airway exposure. Low numbers of particles were found in the circulation (blood, perfusion), bone marrow, brain, heart, liver and spleen but not in eye, muscle, skin, tongue, ovaries, uterus or urine. These data show that the tissue targets of nano- and micron-sized spheres are very similar whether exposure occurs systemically or via the airways while the proportion of particles in some tissues and tissue clearance varies based on particle size.
authors.affiliation: The Procter & Gamble Company, Cincinnati, OH 45253, United States. Sarlo.k@pg.com
authors.forename: Katherine
authors.initials: K
authors.lastname: Sarlo
authors.forename: Karen L
authors.initials: KL
authors.lastname: Blackburn
authors.forename: Edwin D
authors.initials: ED
authors.lastname: Clark
authors.forename: Jeff
authors.initials: J
authors.lastname: Grothaus
authors.forename: Joel
authors.initials: J
authors.lastname: Chaney
authors.forename: Suzanne
authors.initials: S
authors.lastname: Neu
authors.forename: Janine
authors.initials: J
authors.lastname: Flood
authors.forename: Dana
authors.initials: D
authors.lastname: Abbott
authors.forename: Clarence
authors.initials: C
authors.lastname: Bohne
authors.forename: Keith
authors.initials: K
authors.lastname: Casey
authors.forename: Charles
authors.initials: C
authors.lastname: Fryer
authors.forename: Mike
authors.initials: M
authors.lastname: Kuhn
mesh_terms: D000280:Administration, Inhalation; D000284:Administration, Oral; D000818:Animals; D005243:Feces / Q000737:chemistry; D005260:Female; D017408:Guidelines as Topic; D006207:Half-Life; D019570:Inhalation Exposure; D007275:Injections, Intravenous; D008099:Liver / Q000378:metabolism; D008168:Lung / Q000378:metabolism; D054118:Nanospheres / Q000008:administration & dosage* / Q000737:chemistry* / Q000648:ultrastructure; D010316:Particle Size; D011137:Polystyrenes / Q000008:administration & dosage / Q000493:pharmacokinetics*; D011897:Random Allocation; D051381:Rats; D011916:Rats, Inbred F344; D013154:Spleen / Q000378:metabolism; D013950:Thymus Gland / Q000378:metabolism; D014018:Tissue Distribution
chemical_list: D011137:Polystyrenes; C024075:styrofoam