Comparative cardiopulmonary toxicity of exhausts from soy-based biofuels and diesel in healthy and hypertensive rats

Abstract

Increased use of renewable energy sources raise concerns about health effects of new emissions. We analyzed 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 (WKY) and spontaneously hypertensive rats were exposed to these three exhausts at 0, 50, 150 and 500 μg/m3, 4 h/day for 2 days or 4 weeks (5 days/week). In addition, WKY rats were exposed for 1 day and responses were analyzed 0 h, 1 day or 4 days later for time-course assessment. 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 vasoconstriction, thrombosis and atherogenesis were analyzed. The presence of pigmented macrophages in the lung alveoli was clearly evident with all three exhausts without apparent pathology. Overall, exposure to all three exhausts produced only modest effects in most endpoints analyzed in both strains. BALF γ-glutamyl transferase (GGT) activity was the most consistent marker and was increased in both strains, primarily with B0 (B0>B100>B20). This increase was associated with only modest increases in BALF neutrophils. Small and very acute increases occurred in aorta mRNA markers of vasoconstriction and thrombosis with B100 but not B0 in WKY rats. Our comparative evaluations show modest cardiovascular and pulmonary effects at low concentrations of all exhausts: B0 causing more pulmonary injury and B100 more acute vascular effects. BALF GGT activity could serve as a sensitive biomarker of inhaled pollutants.

Comparative study on gene expression profile in rat lung after repeated exposure to diesel and biodiesel exhausts upstream and downstream of a particle filter

“…At the animal level, repeated subacute exposure to RF0 and B30 exhausts was not 378 accompanied by apparent toxicity, except a lower weight gain for rats exposed to RF0 379 upstream DPF. The absence of lung tissue injuries in rats exposed to diesel exhausts are in 380 accordance with previous reports showing modest lung adverse effects of chronic soybean 381 (Bass et al, 2015;Finch et al, 2002) or rapeseed oil-derived fuel exposure in rats (Magnusson 382 et al, 2017 concentrations, the number of regulated genes by B30 emissions was higher downstream than 404 upstream the DPF. Such data were rather surprising since an opposite situation was previously observed in cardiac tissue of rats exposed to diesel emissions (Karoui et al, 2019), suggesting 406 some specific tissue response to gas phase of exhaust or to remaining ultrafine PM.…”

Diesel exhaust impairs TREM2 to dysregulate neuroinflammation

“…Both mice and rats were used in this study, as they have been shown to exhibit similar toxicological and pulmonary responses to DE exposure [ 35 , 36 ]. Twelve-to-fourteen-week-old male Wistar Kyoto (WKY) rats ( n = 7 per group) were obtained from Charles River Laboratories Inc. (Raleigh, NC, USA).…”

“…WKY rats were exposed to whole DE in whole-body chambers for 4 h/day, 5 days/week, for 1 month to filtered air (FA, 0 μg/m 3 ) control or DE (50 μg/m 3 , 150 μg/m 3 , or 500 μg/m 3 ). These concentrations represent an occupational exposure and are an established model of air pollution-induced cardiopulmonary system [ 36 , 39 , 44 ] and CNS damage [ 37 ].…”

Atypical microglial response to biodiesel exhaust in healthy and hypertensive rats

“…Nitrogen dioxide (NO 2 ) levels were obtained by subtracting NO values from total NO x . Further details are provided in previous publications (Mutlu et al,2015; Bass et al, 2015).…”

“…While this suggests the potential for health benefits, the effects of each exhaust might be unique to the organ system examined. For example, biodiesel has been shown to result in acute pulmonary inflammation similar to petroleum diesel (Mehus et al , 2015), but also elevated acute vascular effects (Bass et al , 2015), significant increased liver and lung tissue damage (Shvedova et al , 2013), elevated pulmonary and liver oxidative stress (Shvedova, Yanamala, 2013), and more pronounced pro-inflammatory pulmonary responses (Shvedova, Yanamala, 2013). At present, the impact of biofuel in the brain is largely unknown.…”