10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
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Inhibition of Sub-Chronic Toxicity of Halloysite Nanotubes Aerosol by Enhancing Autophagy in Vivo and in Vitro
RUI RONG, Yongming Zhang, Qixing Zhang, University of Science and Technology of China
Abstract Number: 618 Working Group: Aerosol Toxicology
Abstract Nanoclay is the component of airborne particles that causes serious respiratory diseases. Natural halloysite nanotubes (HNTs) [1] (one dimensional aluminosilicate tubular clay) represent one of the most important nanoclays, which are available on the thousand ton scale worldwide. Among various kinds of exposure ways [2], inhalation is the actual exposure route for human to be exposed to nanoparticles in general and workplace environments. It is therefore essential to study the inhalation toxic effects of HNTs to ensure occupational and consumer safety.
In this work, we designed a nose-only inhalation device and an inhalation exposure system that could appropriately generate and characterize the exposure atmosphere. An aerodynamic particle sizer (APS) (size range: 0.5–20 μm) and fast particulate analyzer (FPA) (size range: 5–1000 nm) were utilized together in tandem to efficiently monitor the particle size and distribution. By applying this system, only the nose of the subject mice were exposed to the aerosol, which allowed for exact dosing. This newly quantitative nose-only inhalation system is of great potential for the research of airborne particle toxicity.
By using of this newly designed inhalation system we evaluated the toxicity of inhaled HNTs comprehensively for different doses (2, 15, 45 mg/m3) and periods (1 week, 2 weeks, 4 weeks). By assessing oxidative stress, inflammatory response, and autophagy, it is found that HNTs can cause sub-chronic toxicity in mice and not recover after two weeks of post-exposure. Most importantly, we found that the toxicity of HNTs can be suppressed by enhancing autophagy. We further investigated the autophagic process on the cellular level to establish the underlying mechanism of HNTs induced autophagy. It is found that the inflammatory response were negatively regulated by autophagy in Human epithelial carcinoma (Hela) cells and alveolar macrophages (AMs) separated from bronchoalveolar lavage fluid (BALF).
References [1] Rong R, et al. "Facile preparation of homogeneous and length controllable halloysite nanotubes by ultrasonic scission and uniform viscosity centrifugation." Chemical Engineering Journal 291 (2016): 20-29. [2] Yan XC, Rong R; et al. "Effects of ZnO nanoparticles on dimethoate-induced toxicity in mice." Journal of agricultural and food chemistry 63.37 (2015): 8292-8298.