Differential pulmonary effects of wintertime California and China particulate matter in healthy young mice

Abstract

Airborne particulate matter (PM) is a global concern because exposure is associated with adverse cardiorespiratory effects. To better understand source-orientated PM toxicity, a comparative study of the biological effects of fine PM (diameter ≤ 2.5 µm, PM2.5) from two geographically different regions of the world known for high PM air pollution, Shanxi Province in China and the Central Valley in California in the United States was conducted on an equal mass basis. PM2.5 was collected in the capital cities of Shanxi Province (Taiyuan) and California (Sacramento) during the winter season. The overarching hypothesis for this study was to test whether the chemical composition of particulate matter on an equal mass basis from two urban areas, one in China and one in California, can lead to significantly different effects of acute toxicity and inflammation in the lungs of healthy young mice. Male, 8-week old BALB/C mice (n=10/group) were given a single 50 µg dose of vehicle, Taiyuan PM or Sacramento PM by oropharyngeal aspiration. Animals were sacrificed 24 hours later to capture peak inflammation following exposure. Bronchoalveolar lavage, ELISA and histopathology were performed to determine biological effects, along with chemical analysis of PM composition. Sacramento PM was found to have a greater proportion of oxidized organic material than Taiyuan PM. Additionally, Sacramento PM was associated with significantly increased neutrophil numbers and elevated CXCL-1 and TNF-α protein levels compared to the Taiyuan PM. The findings suggest, on an equal mass basis, Sacramento PM was associated with a greater inflammatory response compared to that of Taiyuan PM that could be driven by a higher oxidized state of organic carbon and possibly greater copper content.

Pulmonary Health Effects Following Repeated Exposure and Cessation to Wintertime Particulate Matter from California and China

“…Methods in the present study have been reported previously [21,22] but are restated herein for reader accessibility.…”

“…Chemical species such as nitrate, sulfate, chloride, ammonium, and organic compounds were quantified [24]. The organic compounds were fragmented and further analyzed to determine their elemental composition (as regards hydrogen, carbon, oxygen, and nitrogen) and average degree of oxidation as detailed by Aiken et al [25], Ghio et al [26], Sun et al [21], and Zhang et al [22].…”

“…Each mouse was given 50 µL of Milli-Q water, PM CA , PM SD , or PM SX via OPA such that the exposure volume was consistent across all groups as was each single PM mass (20 µg) for all PM-exposed groups. A single dose of this nature has been used previously [21] to examine PM effects. With high ambient PM levels noted in each of the sampled cities (in particular China), a total PM dose of 100 μg administered over a two-week period could approach levels experienced by inhalation of ambient air over this same period of time.…”

“…To elucidate the effects of repeated exposure to source-oriented PM in the present study, we compared the inflammatory responses produced by different regional PM 2.5 extracts administered via oropharyngeal aspiration over multiple days. Although comparative analyses of pulmonary inflammatory responses to PM from California and China have been reported [21,22], the present study is the first to assess the differential time-lag effects of repeated exposure to PM from Sacramento, Jinan, and Taiyuan. Results from the present study are discussed in relation to previous findings [21,22] to further illustrate how different exposure paradigms influence observed responses.…”

A Time and a Place for Everything: Aligning Community-Engaged Research to Context

“…London had worked with both EJCW and CCV on earlier environmental justice research projects and Andrade had significant experience with CBPR. The CEC then sought out EHSC-affiliated faculty with relevant expertise and identified Kent Pinkerton and his lab, which is internationally renowned for its expertise in the respiratory health effects of air pollutants [42][43][44][45][46]. With assistance from the CEC the Pinkerton lab worked with CCV and EJCW to develop a proposal for a project that would draw upon the local expertise of the community and university expertise in the respiratory health effects of particulate pollution.…”