Host: The Japanese Society of Toxicology
Name : The 47th Annual Meeting of the Japanese Society of Toxicology
Date : 2020 -
【Introduction】With the increasing use of nanoparticles in various consumer products, concerns have been raised to the environmental and biological impact of nanoparticles. Indium compounds are known as an important material in flat panel displays and semiconductor compounds, and the Ministry of Health, Labor and Welfare added indium compound to substances regulated by the Ordinance on Prevention of Hazards Due to Specified Chemical Substances (OPHSCS) in 2013. Single particle (SP)-ICP-MS is a new method to analyze nanoparticles that utilizes the features of ICP-MS, such as high sensitivity, high selectivity, rapid measurement, and simple data processing. This technique has been established as a method that can measure the size, size distribution, and particle concentration. The aim of this study was to clarify the presence of indium nanoparticles in serum after intratracheal instillation of indium tin oxide (ITO）nanoparticles.
【Materials and Methods】Male Wistar rats were intratracheally instilled with a single dose of 8.6 mg In/kg BW (4 rats) or 25.8 mg In/kg BW (4 rats) of ITO nanoparticles (mean diameter:18 nm, 99.5% , 20 wt % in H2O), and control rats (2 rats) were instilled with 1ml/kg distilled water. Rats in the test group were euthanized until 40 weeks after the instillation, and then number of indium (In) nanoparticles in serum was determined using SP-ICP-MS (PerkinElmer NexION ICP-MS).
【Results】Indium nanoparticles were detected in serum for all rats treated with ITO nanoparticles, but not in the controls. The ratio of serum Indium particle concentration to all serum Indium concentration was 3 to 6 % in the 8.6 mg In/kg BW group and 2 to 28 % in the 25.8 mg In/kg BW group.
It was considered that some of the ITO nanoparticles instilled to the lungs were transferred to the internal organs by systemic circulation.
