Details

Autor(en) / Beteiligte

• Zhang, Guihua
• Shinohara, Naohide
• Kano, Hirokazu
• Senoh, Hideki
• Suzuki, Masaaki
• Sasaki, Takeshi
• Fukushima, Shoji
• Gamo, Masashi

Titel

Quantitative evaluation of local pulmonary distribution of TiO sub(2) in rats following single or multiple intratracheal administrations of TiO sub(2) nanoparticles using X-ray fluorescence microscopy

Ist Teil von

• Journal of applied toxicology, 2016-10, Vol.36 (10), p.1268-1275

Erscheinungsjahr

2016

Quelle

Wiley Online Library

Beschreibungen/Notizen

• Uneven pulmonary nanoparticle (NP) distribution has been described when using single-dose intratracheal administration tests. Multiple-dose intratracheal administrations with small quantities of NPs are expected to improve the unevenness of each dose. The differences in local pulmonary NP distribution (called microdistribution) between single- and multiple-dose administrations may cause differential pulmonary responses; however, this has not been evaluated. Here, we quantitatively evaluated the pulmonary microdistribution (per mesh: 100 mu m 100 mu m) of TiO sub(2) in lung sections from rats following one, two, three, or four doses of TiO sub(2) NPs at a same total dosage of 10 mg kg super(-1) using X-ray fluorescence microscopy. The results indicate that: (i) multiple-dose administrations show lower variations in TiO sub(2) content (ng mesh super(-1)) for sections of each lobe; (ii) TiO sub(2) appears to be deposited more in the right caudal and accessory lobes located downstream of the administration direction of NP suspensions, and less so in the right middle lobes, irrespective of the number of doses; (iii) there are not prominent differences in the pattern of pulmonary TiO sub(2) microdistribution between rats following single and multiple doses of TiO sub(2) NPs. Additionally, the estimation of pulmonary TiO sub(2) deposition for multiple-dose administrations imply that every dose of TiO sub(2) would be randomly deposited only in part of the fixed 30-50% of lung areas. The evidence suggests that multiple-dose administrations do not offer remarkable advantages over single-dose administration on the pulmonary NP microdistribution, although multiple-dose administrations may reduce variations in the TiO sub(2) content for each lung lobe. We quantitatively evaluated the pulmonary microdistribution (per mesh: 100 mu m100 mu m) of TiO sub(2) in lung sections from rats following one, two, three, or four doses of TiO sub(2) NPs at a same total dosage of 10mg kg super(-1) using X-ray fluorescence microscopy. The evidence suggests that multiple-dose administrations do not offer remarkable advantages over single-dose administration on the pulmonary NP microdistribution, although multiple-dose administrations may reduce the variations in TiO sub(2) content for each lung lobe.