ToxSci Advance Access originally published online on March 30, 2009
Toxicological Sciences 2009 109(2):372-380; doi:10.1093/toxsci/kfp064
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High Doses of Intravenously Administered Titanium Dioxide Nanoparticles Accumulate in the Kidneys of Rainbow Trout but with no Observable Impairment of Renal Function
* Ecotoxicology and Aquatic Biology Research Group, Hatherly Laboratories, University of Exeter, Exeter EX4 4PS, Devon, UK
School of Geography, Earth, and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
School of Biosciences, University of Westminster, London W1W 6UW, UK
1 To whom correspondence should be addressed at Ecotoxicology and Aquatic Biology Research Group, Hatherly Laboratories, University of Exeter, Prince of Wales Road, Exeter EX4 4PS, Devon, UK. Fax: +44-1392-263434. E-mail: c.r.tyler{at}exeter.ac.uk.
Received December 10, 2008; accepted March 25, 2009
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Abstract |
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Our recent work suggests limited uptake of unstabilized metal oxide nanoparticles via water into fish, however, some other studies have indicated such exposures can induce oxidative stress. To investigate tissue distribution and toxicity of titanium dioxide (TiO2) nanoparticles that may enter into fish, we conducted a series of injection studies. Rainbow trout (Oncorhynchus mykiss) were intravenously injected with 100 µg TiO2 nanoparticles and the content of titanium in blood, brain, gills, liver, and kidney quantified at time points between 6 h and 90 days using inductively coupled plasma optical emission spectroscopy. Injected Ti was concentrated in the kidneys and remained there up to 21 days, however, there was evidence of clearance of TiO2 at 90 days. Ti accumulation in the liver was 15 times lower than in the kidney with no apparent clearance. Using TEM we showed nanoparticles were localized in tissue vesicles surrounding the kidney tubules. In a second injection study, rainbow trout were injected with 100 µg TiO2 and plasma samples from individual fish analyzed for total protein and creatinine content at time points between 6 h and 21 days to assess for possible effects on kidney function. No effect of TiO2 on total plasma protein content or creatinine concentrations were found indicating that neither urine production nor glomerular filtration rate were affected. We conclude that in trout upon a single high dose exposure of TiO2 nanoparticles via the bloodstream, TiO2 accumulates in the kidneys but has minimal effect on kidney function.
Key Words: titanium dioxide; rainbow trout; lipid peroxidation; intravenous injection; nanoparticles; nanotoxicology.