Subacute inhalation toxicity study of synthetic amorphous silica nanoparticles in Sprague-Dawley rats

• Published in: Inhalation toxicology Vol. 29; no. 12-14; pp. 567 - 576
• Main Authors: Shin, Jae Hoon, Jeon, KiSoo, Kim, Jin Kwon, Kim, Younghun, Jo, Mi Seong, Lee, Jong Seong, Baek, Jin Ee, Park, Hye Seon, An, Hyo Jin, Park, Jung Duck, Ahn, Kangho, Oh, Seung Min, Yu, Il Je
• Format: Journal Article
• Language: English
• Published: England Taylor & Francis 06-12-2017
• Subjects: Aerosols - administration & dosage; Aerosols - metabolism; Aerosols - toxicity; Amorphous silica; Animals; Inhalation Exposure - adverse effects; inhalation toxicity; Lung - drug effects; Lung - metabolism; Male; Nanoparticles - administration & dosage; Nanoparticles - metabolism; Nanoparticles - toxicity; nanosilica; Rats; Rats, Sprague-Dawley; Silicon Dioxide - administration & dosage; Silicon Dioxide - metabolism; Silicon Dioxide - toxicity; subacute; Tissue Distribution - drug effects; Tissue Distribution - physiology; subacute; inhalation toxicity; nanosilica; Amorphous silica
• ISSN: 0895-8378; 1091-7691
• DOI: 10.1080/08958378.2018.1426661

Synthetic amorphous silica nanoparticles (SiNPs) are one of the most applied nanomaterials and are widely used in a broad variety of industrial and biomedical fields. However, no recent long-term inhalation studies evaluating the toxicity of SiNPs are available and results of acute studies are limited. Thus, we conducted a subacute inhalation toxicity study of SiNPs in Sprague-Dawley rats using a nose-only inhalation system. Rats were separated into four groups and target concentrations selected in this study were as follows: control (fresh air), low- (0.407 ± 0.066 mg/m
3
), middle- (1.439 ± 0.177 mg/m
3
) and high-concentration group (5.386 ± 0.729 mg/m
3
), respectively. The rats were exposed to SiNPs for four consecutive weeks (6 hr/day, 5 days/week) except for control group of rats which received filtered fresh air. After 28-days of inhalation exposure to SiNPs, rats were sacrificed after recovery periods of one, seven and 28 days. Although there were minimal toxic changes such as temporary decrease of body weight after exposure, increased levels of red blood cells (RBCs) and hemoglobin (Hb) concentration, the lung histopathological findings and inflammatory markers in bronchoalveolar lavage (BAL) fluid including polymorphonuclear (PMN) leukocyte, lactate dehydrogenase (LDH), albumin and protein did not show significant changes at any recovery period. The results of this study suggest that the subacute inhalation of SiNPs had no toxic effects on the lung of rats at the concentrations and selected time points used in this study.