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Comparative cardiopulmonary toxicity of soy biofuel and diesel exhaust in healthy and hypertensive rats
Citation:
Schladweiler, M., V. Bass, R. Thomas, J. Richards, D. Johnson, D. Andrews, A. Nyska, Todd Krantz, C. King, AND U. Kodavanti. Comparative cardiopulmonary toxicity of soy biofuel and diesel exhaust in healthy and hypertensive rats. Presented at Society of Toxicology, March 09 - 14, 2013.
Impact/Purpose:
This abstract examines relative toxicities of diesel exhaust and biodiesel exhausts. Toxicological evaluations show modest cardiovascular and pulmonary effects at low concentrations of all exhausts. Additionally, this study highlights the value of lavage fluid levels of GGT activity as the most sensitive biomarker in low level inhalation studies.
Description:
Increased use of renewable energy sources raise concerns about health effects of emissions from such sources. We conducted a comprehensive analysis of relative cardiopulmonary health effects of exhausts from 1) 100% soy biofuel (B100), 2) 20% soy biofuel + 80% low sulfur petroleum diesel (B20), and 3) 100% petroleum diesel (B0) in rats. Normotensive Wistar Kyoto and spontaneously hypertensive rats were exposed to these 3 exhausts at 0, 50, 150 and 500 g/m3, 4 h/day for either 2d or 4 wk (5 d/wk) to mimic near environmental concentrations. Additionally, WKY rats were exposed for 1d and responses were analyzed 0 hr, 1d or 4d later for time course analysis. Hematological parameters, in vitro platelet aggregation, bronchoalveolar lavage fluid (BALF) markers of pulmonary injury and inflammation, ex-vivo aortic ring constriction, heart and aorta mRNA markers of atherogenesis, and serum biomarkers of acute cardiac injury as well as cytokines were analyzed. The presence of pigmented macrophages in the lung alveoli was clearly evident with all 3 exhaust exposures. Overall, exposure to all 3 exhausts produced only modest effects in most endpoints analyzed in both rat strains. BALF -glutamyl transferase (GGT) activity was the most consistent marker shown to be increased in both strains with all 3 fuels (B0>B100>B20) without increases in BALF neutrophils. Small inconsistent changes in aorta mRNA markers of inflammation, vasoconstriction and thrombosis, and those of serum biomarkers need to be interpreted cautiously. Our comparative evaluations show modest cardiovascular and pulmonary effects at low concentrations of all exhausts. Additionally, our study highlights the value of BALF levels of GGT activity as the most sensitive biomarker in low level inhalation studies. (This abstract does not represent USEPA policy).