Effect of silver nanowires with fiber length on lung by intratracheal instillation

Research Project

Project/Area Number	15K08789
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Multi-year Fund
Section	一般
Research Field	Hygiene and public health
Research Institution	University of Occupational and Environmental Health, Japan
Principal Investigator	OYABU Takako 産業医科大学, 産業生態科学研究所, 講師 (20320369)
Co-Investigator(Kenkyū-buntansha)	明星敏彦産業医科大学, 産業生態科学研究所, 教授 (00209959)
Project Period (FY)	2015-04-01 – 2018-03-31
Project Status	Completed (Fiscal Year 2017)
Budget Amount *help	¥4,810,000 (Direct Cost: ¥3,700,000、Indirect Cost: ¥1,110,000) Fiscal Year 2017: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000) Fiscal Year 2016: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000) Fiscal Year 2015: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000)
Keywords	銀ナノワイヤー / 気管内注入試験 / 実験動物 / BALF中好中球 / 病理組織変化 / 肺の炎症 / 肺内滞留性 / 金属ナノワイヤーの生体影響 / 病理組織評価
Outline of Final Research Achievements	For investigating the effect of length of silver nanowires on the hazard to the lungs, we performed the in vivo intratracheal instillation experiment. We made the shorter nanowires from the commercialized silver nanowires and performed the in vivo experiment and compare the biological effects. The geometric mean lengths of the original and shorter wires were 12.4 and 1.2 micro-m and the diameters of both wires were 62-64 nm. We performed intratracheal instillation examination of these 2 nanowires to rats, and evaluated the total cell, PMN counts and LDH activity in the BALF and histopathological change in lung. The increase of these indicators in BALF and tissue changes were remarkable at 3 days after the instillation of both wires. After 1 month, the reactions of the original wires were decreased but those of shorter wires were maintained. After 3 months, those of both wires were gradually diminished. From these results, shorter silver nanowires are more reactive than longer wires.