Seasonal Variations in Air Pollution Particle-Induced Inflammatory Mediator Release and Oxidative Stress

Abstract

Health effects associated with particulate matter (PM) show seasonal variations. We hypothesized that these heterogeneous effects may be attributed partly to the differences in the elemental composition of PM. Normal human bronchial epithelial (NHBE) cells and alveolar macrophages (AMs) were exposed to equal mass of coarse [PM with aerodynamic diameter of 2.5-10 µm (PM 2.5-10 )], fine (PM 2.5 ), and ultrafine (PM < 0.1 ) ambient PM from Chapel Hill, North Carolina, during October 2001 (fall) and January (winter), April (spring), and July (summer) 2002. Production of interleukin (IL)-8, IL-6, and reactive oxygen species (ROS) was measured. Coarse PM was more potent in inducing cytokines, but not ROSs, than was fine or ultrafine PM. In AMs, the October coarse PM was the most potent stimulator for IL-6 release, whereas the July PM consistently stimulated the highest ROS production measured by dichlorofluorescein acetate and dihydrorhodamine 123 (DHR). In NHBE cells, the January and the October PM were consistently the strongest stimulators for IL-8 and ROS, respectively. The July PM increased only ROS measured by DHR. PM had minimal effects on chemiluminescence. Principal-component analysis on elemental constituents of PM of all size fractions identified two factors, Cr/Al/Si/Ti/Fe/Cu and Zn/As/V/Ni/Pb/Se, with only the first factor correlating with IL-6/IL-8 release. Among the elements in the first factor, Fe and Si correlated with IL-6 release, whereas Cr correlated with IL-8 release. These positive correlations were confirmed in additional experiments with PM from all 12 months. These results indicate that elemental constituents of PM may in part account for the seasonal variations in PM-induced adverse health effects related to lung inflammation. Key words: air pollutant, interleukin-6, interleukin-8, reactive oxygen species.

The role of oxidative stress in ambient particulate matter-induced lung diseases and its implications in the toxicity of engineered nanoparticles

“…One study conducted by Becker et al showed that PM10 stimulated IL-8 and ROS production normal human bronchial epithelial (NHBE) cells and IL-6 production in alveolar macrophages. Further analyses of the principal components indicated that while Fe and Si in the PM correlated with IL-6 release, Cr correlated with IL-8 increase [32]. Soluble metals on inhaled PM have been shown to induce cellular oxidative stress in airway epithelial cells.…”

Compound Danshen injection improves endotoxin-induced microcirculatory disturbance in rat mesentery

“…The DHR passively diffuses across the cell membranes, where it is oxidized to cationic rhodamine 123 and localizes in the mitochondria. After labeling, the cells were treated with both compound Danshen injection (0.2 μL/mL, 0.5 μL/mL and 1.0 μL/mL, respectively) and LPS (2 μg/mL) for 20 min on ice, the production of hydrogen peroxide was then determined by flow cytometry by measuring emission at 590 nm for DHR [27] .…”

Physical Characterization of the University of Toronto Coarse, Fine, and Ultrafine High-Volume Particle Concentrator Systems

“…Although the correlation between particulate matter (PM) exposure and adverse health effects is generally positive, the magnitude of associations varies with different geographic locations and seasons. Such variability has been attributed in part to the geographical and seasonal distribution of PM composition (Samet et al 2000;Becker et al 2005;Zereini and Wiseman 2011). Fine (aerodynamic diameter <2.5 µm) and ultrafine (aerodynamic diameter <100 nm) PM are of specific concern because of their larger surface area/particle number and potential to penetrate the lungs all the way to the alveolar/capillary border (Oberdorster et al 2005).…”