Arabidopsis thaliana as a bioindicator of the ability of atmospheric particulate matter to induce oxidative stress in living organisms

It is now recognized that one of the main mechanisms by which atmospheric particulate matter (PM) exerts its adverse health effects is the generation of oxidative stress [1-3]. Therefore, over the past few years, several acellular assays, which can be performed quickly and at a relatively low cost, have been developed to measure PM’s oxidative potential (OP). However, these assays cannot represent the complexity of a biological organism and cannot provide us with complete information on the toxicological potential of PM [1-4]. The use of both plant [1] and animal [3] model organisms could provide more detailed information about the ability of PM to generate oxidative stress in living organisms [1,3]. The main objective of this study is to develop and optimize a simple, rapid, and low-cost method to study the oxidative stress effects induced by PM exposure using the plant model organism Arabidopsis thaliana. Seedlings of A. thaliana were exposed to certified urban particulate matter dust (NIST1648a) and PM2.5 samples taken in the Po Valley, where air pollution occurs frequently due to the presence of several particulate matter emissive sources and extended periods of atmospheric stability. Seedlings were grown for 14 days in growth chambers under controlled conditions and exposed to increasing concentrations of NIST1648a (0.5, 1, 2, and 5 g/L) and PM2.5 samples. The presence of oxidative stress was assessed by visualization and quantification of superoxide anion (·O2-) production using the Nitroblue tetrazole (NBT) assay, which is based on the highly specific reaction that occurs between NBT and ·O2- that leads to the formation of a blue-purple precipitate (formazan) measured by UV-Vis spectrometer. The results obtained in this study showed that both types of dust generate oxidative stress in all exposed seedlings, leading to an increase in ROS of up to 64% compared with the control. Furthermore, the data obtained show that the presence of stress increases in a concentration- and in dust ‘s chemical composition-dependent manner. Through the application of this method, it is possible to obtain information about the ability of PM to generate oxidative stress in living organisms quickly and keeping costs relatively low.