Inflammatory and functional responses after (bio)diesel exhaust exposure in allergic sensitized mice. A comparison between diesel and biodiesel.

Many cities fail to meet air quality standards, which results in increased risk for pulmonary disorders, including asthma. Human and experimental studies have shown that diesel exhaust (DE) particles are associated with worsening of allergic asthma. Biodiesel (BD), a cleaner fuel from renewable sources, was introduced in the eighties. Because of the reduction in particulate matter (PM) emissions, BD was expected to cause fewer adverse pulmonary effects. However, only limited data on the effect of BD emissions in asthma are available. OBJECTIVE: Determine whether BD exhaust exposure in allergic sensitized mice leads to different effects on inflammatory and functional responses compared to DE exposure. METHODS: Balb/C mice were orotracheally sensitized with House Dust Mite (HDM) or a saline solution with 3 weekly instillations. From day 9 until day 17 after sensitization, they were exposed daily to filtered air (FA), DE and BD exhaust (concentration: 600 µg/m3 PM2.5). Lung function, bronchoalveolar lavage fluid (BALF) cell counts, cytokine levels (IL-2, IL-4, IL-5, IL-17, TNF-α, TSLP) in the BALF, peribronchiolar eosinophils and parenchymal macrophages were measured. RESULTS: HDM-sensitized animals presented increased lung elastance (p = 0.046), IgG1 serum levels (p = 0.029), peribronchiolar eosinophils (p = 0.028), BALF levels of total cells (p = 0.020), eosinophils (p = 0.028), IL-5 levels (p = 0.002) and TSLP levels (p = 0.046) in BALF. DE exposure alone increased lung elastance (p = 0.000) and BALF IL-4 levels (p = 0.045), whereas BD exposure alone increased BALF TSLP levels (p = 0.004). BD exposure did not influence any parameters after HDM challenge, while DE exposed animals presented increased BALF levels of total cells (p = 0.019), lymphocytes (p = 0.000), neutrophils (p = 0.040), macrophages (p = 0.034), BALF IL-4 levels (p = 0.028), and macrophagic inflammation in the lung tissue (p = 0.037), as well as decreased IgG1 (p = 0.046) and IgG2 (p = 0.043) levels when compared to the HDM group. CONCLUSION: The results indicate more adverse pulmonary effects of DE compared to BD exposure in allergic sensitized animals.

Tradescantia pallida cv. purpurea boom in the characterization of air pollution by accumulation of trace elements.

Tradescantia pallida cv. purpurea, a plant species widely employed for ornamentation in Brazil, has been successfully used for monitoring the genotoxicity of various agents by the micronucleus assay. To amplify knowledge about its suitability as a bioindicator species, its capacity for accumulating trace elements from urban air pollution was evaluated. T. pallida was rooted using standardized soil, and the vases were distributed in two highly polluted sites of the urban area of São Paulo, Brazil (Cerqueira Cesar and Congonhas districts), and in one unpolluted control site situated approximately 50 km from downtown São Paulo (in Caucaia do Alto). Approximately six months after exposure to pollutants, adult leaves of this plant were collected monthly for 12 months. The leaves were washed with deionized water, dried, and ground for analyses. Characterization of element levels was carried out by neutron activation analysis. Powdered samples and standards were irradiated at the IEA-R1 nuclear reactor for short and long periods, and concentrations of As, Ba, Br, Ca, Ce, Cl, Cr, Co, Fe, K, La, Mn, Na, Rb, Sb, Sc, Sr, Th, and Zn were determined. Analysis of variance applied to the results indicated that samples from polluted sites present the highest concentrations of Ba, Ce, Cr, Co, Fe, La, Sb, and Sc (p < 0.05). Discriminant analysis revealed that it was possible to distinguish the two polluted areas with a precision of 97.5%, based on the amount of pollutant elements measured in the plants at each site. The results indicated the potential use of T. pallida as an accumulator plant for air pollution biomonitoring.