Cellular and Acellular Assays for Measuring Oxidative Stress Induced by Ambient and Laboratory-Generated Aerosols

• Published in: Research report - Health Effects Institute 2019-03, Vol.2019 (197), p.1
• Main Authors: Ng, N L, Tuet, W Y, Chen, Y, Fok, S, Gao, D, Tagle Rodriguez, M S, Klein, M, Grosberg, A, Weber, R J, Champion, J A
• Format: Article
• Language: English
• Subjects: Aerosols - metabolism; Aerosols - pharmacology; Biological Assay; Humans; Laboratories; Oxidative Stress - drug effects; Particulate Matter - analysis; Particulate Matter - metabolism; Particulate Matter - pharmacology; Walter A. Rosenblith New Investigator Award
• ISSN: 1041-5505; 2688-6855

Many studies have established associations between exposure to air pollution, or atmospheric particulate matter (PM), and adverse health effects. An increasing array of studies have suggested oxidative stress as a possible mechanism by which PM-induced health effects arise, and as a result, many chemical and cellular assays have been developed to study PM-induced oxidant production. Although significant progress has been made in recent years, there are still many gaps in this area of research that have not been addressed. Many prior studies have focused on the aerosol of primary origin (e.g., the aerosol emitted from combustion engines) although the aerosol formed from the oxidation of volatile species, secondary organic aerosol (SOA), has been shown to be the predominant type of aerosol even in urban areas. Current SOA health studies are limited in number, and as such, the health effects of SOA are poorly characterized. Also, there is a lack of perspective in terms of the relative toxicities of different SOA systems. Additionally, although chemical assays have identified some SOA constituents associated with adverse health endpoints, the applicability of these results to cellular responses has not been well established. The overall objective of this study was to better understand the oxidative properties of different types and components of PM mixtures (especially SOA) through systematic laboratory chamber experiments and ambient field studies. The study had four specific aims. 1 To develop a cellular assay optimized for measuring reactive oxygen and nitrogen species (ROS/RNS) production resulting from PM exposure and to identify a robust parameter that could represent ROS/RNS levels for comparison with different endpoints. 2 To identify ambient PM components associated with ROS/RNS production and evaluate whether results from chemical assays represented cellular responses in terms of ROS/RNS production. 3 To investigate and provide perspective on the relative toxicities of SOA formed from common biogenic and anthropogenic precursors under different conditions (e.g., humidity, nitrogen oxides [NO ], and redox-active metals) and identify bulk aerosol properties associated with cellular responses. 4 To investigate the effects of photochemical aging on aerosol toxicity. Ambient PM samples were collected from urban and rural sites in the greater Atlanta area as part of the Southeastern Center for Air Pollution and Epidemiology (SCAPE) study between June 2012