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Diesel and biodiesel exhaust particle effects on rat alveolar machrophages with in vitro exposure
Bhavaraju, L., J. Shannahan, A. Williams, R. McCormick, J. Mcgee, U. Kodavanti, AND M. Madden. Diesel and biodiesel exhaust particle effects on rat alveolar machrophages with in vitro exposure. CHEMOSPHERE. Elsevier Science Ltd, New York, NY, 104:126-33, (2014).
Our goal in this study was to examine the macrophage response and the consequential arachidonic acid metabolism as a result of in vitro exposure to 20% biodiesel/80% petroleum diesel particulate matter in comparison to petroleum diesel particles alone. We have designed an in vitro approach to study AM endpoints specific to particle exposure. Exposre to biodiesel blend-derived PM in vivo also increases protein and cell count in BALF compared to diesel PM alone We hypothesize the inflammatory response in AMs to BDEP will differ from PDEP. We postulate the intensity of an inflammatory response can be affected by the particle composition and size.
We conducted in vitro exposures of Wistar rat alveolar macrophages (AM) to compare and contrast the toxicity of particulate matter (PM) produced in combustion of biodiesel blend (B20) and petroleum diesel (PDEP). The PM contain detectable levels of transition metals and ions however the particles alone do not produce a detectable TBARS reaction. Both particles initiated an inflammatory response from AM after exposure, as measured by prostaglandin E2 (PGE2) release; B20 exposure resulted in more prostaglandin E2 (PGE2) release than with PDEP exposure. The AM exposure to B20 and PDEP for 24hrs also showed increase expression of both the mRNA of cyclooxygenase-2 (COX2) and macrophage inflammatory protein 2 (MIP2). B20 and PDEP have similar affinity for sequestering PGE2 and occurs to a major extent only at PM concentrations at >100 ug/ml suggesting measurement of the release is minor and not disportionally affected. Our data suggests PGE2 release from cells can change based on the chemical composition of the particles.