Effects of Subchronic Inhalation Exposure of Rats to Emissions From a Diesel Engine Burning Soybean Oil-Derived Biodiesel Fuel

Abstract

There is increasing interest in diesel fuels derived from plant oils or animal fats ("biodiesel"), but little information on the toxicity of biodiesel emissions other than bacterial mutagenicity. F344 rats were exposed by inhalation 6 h/day, 5 days/wk for 13 wk to 1 of 3 dilutions of emissions from a diesel engine burning 100% soybean oil-derived fuel, or to clean air as controls. Whole emissions were diluted to nominal NO(x) concentrations of 5, 25, or 50 ppm, corresponding to approximately 0.04, 0.2, and 0.5 mg particles/m(3), respectively. Biologically significant, exposure-related effects were limited to the lung, were greater in females than in males, and were observed primarily at the highest exposure level. There was a dose-related increase in the numbers of alveolar macrophages and the numbers of particles in the macrophages, as expected from repeated exposure, but no neutrophil response even at the highest exposure level. The macrophage response was reduced 28 days after cessation of the exposure. Among the high-level females, the group mean lung weight/body weight ratio was increased, and minimal, multifocal bronchiolar metaplasia of alveolar ducts was observed in 4 of 30 rats. Lung weights were not significantly increased, and metaplasia of the alveolar ducts was not observed in males. An increase in particle-laden macrophages was the only exposure-related finding in lungs at the intermediate and low levels, with fewer macrophages and fewer particles per macrophage at the low level. Alveolar histiocytosis was observed in a few rats in both exposed and control groups. There were statistically significant, but minor and not consistently exposure-related, differences in body weight, nonpulmonary organ weights, serum chemistry, and glial fibrillary acidic protein in the brain. There were no significant exposure-related effects on survival, clinical signs, feed consumption, ocular toxicity, hematology, neurohistology, micronuclei in bone marrow, sister chromatid exchanges in peripheral blood lymphocytes, fertility, reproductive toxicity, or teratology. This study demonstrated modest adverse effects at the highest exposure level, and none other than the expected physiological macrophage response to repeated particle exposure at the intermediate level.

Oxidative Stress, Inflammatory Biomarkers, and Toxicity in Mouse Lung and Liver after Inhalation Exposure to 100% Biodiesel or Petroleum Diesel Emissions

“…The elevated levels of MCP-1 upon B100 exposure, suggesting an increase in the monocyte/macrophage recruitment to the lung ( Figure 3A), are further paralleled by enhanced MPO activity in lung homogenates compared to D100 ( Figure 1A). An infiltration of macrophages in pulmonary tissue during a subchronic exposure of soybean BD CE was also observed previously (Finch et al, 2002;Brito et al, 2010). Further, exposure to organic fractions of diesel exhaust particles was found to elicit a proinflammatory response in human airway epithelial (Bonvallot et al, 2001) and other cells (Fahy et al, 1999).…”

“…Previous studies on toxicity of BD emissions, other than mutagenicity studies, were performed either in rats over extended time periods (Finch et al, 2002) or in mice involving exposure to 550 μg/m 3 of BD exhaust for only 1 h (Brito et al, 2010). In this study, oxidative stress and inflammatory responses were examined in lung and liver of mice upon inhalation exposure to 50, 150 or 500 μg/m 3 of neat BD (B100) and D (D100) CE, 4 h/d, 5 d/wk, for a total period of 4 wk.…”

“…In particular, Finch et al (2002) exposed F344 rats to biodiesel at concentrations of 40, 200, and 500 μg/m 3 . These exposure concentrations also reflect concentrations in coal mines and other occupations associated with use of diesel equipment (U.S. EPA, 2002).…”

Release of the Pro-Inflammatory Markers by BEAS-2B Cells Following In Vitro Exposure to Biodiesel Extracts

“…Couple this finding to their observation that biodiesel emissions are in the ultrafine PM region and there is a motive for more health effects research. The few cytotoxicity studies on biodiesel SOF have been equivocal [31] but mutagenicity studies demonstrated less mutagenic potency for biodiesel compared to petroleum diesel [15,32]. Biodiesel is the first renewable diesel fuel to show signs of becoming a commercially accepted part of our nation's energy infrastructure.…”

Toxicidade cardiovascular e inflamatória aguda induzida pela inalação de partículas dos combustíveis diesel e biodiesel

“…Em contrapartida, apenas alguns estudos focam na análise do combustível biodiesel em nível de toxicidade (Finch et al, 2002;Khan et al, 2007;Liu et al, 2008) citotoxicidade e mutagenicidade (Carraro et al, 1997;Bunger et al, 1998Bunger et al, , 2000aBunger et al, , 2000bBunger et al, , 2007 …”