BPA levels measured in serum.

a<p>BPA drinking water concentration.</p>b<p>BPA levels were measured before weaning from pups of non-exposed and mother mice exposed during pregnancy and breastfeeding.</p><p>**P<0.01, ***P<0.001 compared to non-exposed control.</p><p>Mother mice were exposed during pregnancy and breastfeeding and adult mice for 5 weeks to BPA via drinking water. BPA serum levels of adult mice or pups were measured at the end of the exposure period as described in Methods.</p

Lifelong exposure to BPA significantly increased the allergic airway inflammation.

<p>Nursing mice were exposed to 5 µg/ml BPA via drinking water and offspring during their lifetime. The asthma phenotype was induced by sensitization to OVA followed by an intrapulmonary allergen challenge as described in Materials and Methods. BPA exposure increased total cell number in BAL fluid (a), lung inflammation (b), lung resistance (c), and OVA-specific IgE serum levels (e). Cytokine production was not affected (e+f). Data are expressed as mean ± SEM, n≥6 animals per group. *P<0.05.</p

Perinatal BPA exposure showed no effect on the asthma phenotype in the offspring.

<p>Mice were exposed to 5 µg/ml BPA via drinking water during pregnancy and breastfeeding. In the offspring an asthma phenotype was induced by sensitization to OVA followed by an intrapulmonary allergen challenge as described in Materials and Methods. BPA exposure did neither affect total cell number in BAL fluid (a), lung inflammation (b), lung resistance (c), OVA-specific IgE serum levels (d) nor cytokine production in splenocytes (e) or lymph node cells (f). Data are expressed as mean ± SEM, n≥22 animals per group. *P<0.05.</p

Prenatal BPA exposure did not affect the asthma phenotype in the offspring.

<p>Mice were exposed to 5 µg/ml BPA via drinking water during pregnancy. In the offspring an asthma phenotype was induced by sensitization to ovalbumin (OVA) followed by an intrapulmonary allergen challenge as described in Materials and Methods. BPA exposure did neither affect total cell number in BAL fluid (a), lung inflammation (b), lung resistance (c), OVA-specific IgE serum levels (d) nor cytokine production in splenocytes (e) or lymph node cells (f). Data are expressed as mean ± SEM, n≥11 animals per group.</p

Glucocorticoid receptor antagonist RU486 abolished the decreased immune response induced by BPA.

<p>Adult mice were exposed to 5 µg/ml BPA via drinking water. RU486 was given intraperitoneally 3 times/week during OVA-immunisation. Treatment with RU486 reversed the BPA-induced effect on total cell number in BAL fluid (a), lung inflammation (b), lung resistance (c) and OVA-specific IgE serum levels (d). Data are expressed as mean ± SEM, n≥5 animals per group. *P<0.05 OVA and ^#P<0.05 OVA+BPA+RU486 <i>vs.</i> OVA+BPA.</p

Exposure of adult mice to BPA during sensitization reduced the allergic immune response.

<p>Adult mice were exposed to 5 µg/ml BPA via drinking water during OVA-immunization. BPA exposure reduced total cell number in BAL fluid (a), lung inflammation (b), lung resistance (c), OVA-specific IgE serum levels (e) and Th2 cytokine production from lymph node cells (f), while cytokine production from spleen was not affected (e). Data are expressed as mean ± SEM, n≥18 animals per group. *P<0.05.</p

Volatile Organic Compounds Enhance Allergic Airway Inflammation in an Experimental Mouse Model

<div><h3>Background</h3><p>Epidemiological studies suggest an association between exposure to volatile organic compounds (VOCs) and adverse allergic and respiratory symptoms. However, whether VOCs exhibit a causal role as adjuvants in asthma development remains unclear.</p> <h3>Methods</h3><p>To investigate the effect of VOC exposure on the development of allergic airway inflammation Balb/c mice were exposed to VOCs emitted by new polyvinylchloride (PVC) flooring, sensitized with ovalbumin (OVA) and characterized in acute and chronic murine asthma models. Furthermore, prevalent evaporated VOCs were analyzed and mice were exposed to selected single VOCs.</p> <h3>Results</h3><p>Exposure of mice to PVC flooring increased eosinophilic lung inflammation and OVA-specific IgE serum levels compared to un-exposed control mice. The increased inflammation was associated with elevated levels of Th2-cytokines. Long-term exposure to PVC flooring exacerbated chronic airway inflammation. VOCs with the highest concentrations emitted by new PVC flooring were N-methyl-2-pyrrolidone (NMP) and 2,2,4-trimethyl-1,3-pentanediol diisobutyrate (TXIB). Exposure to NMP or TXIB also increased the allergic immune response in OVA-sensitized mice. <em>In vitro</em> or <em>in vivo</em> exposure to NMP or TXIB reduced IL-12 production in maturing dendritic cells (DCs) and enhanced airway inflammation after adoptive DC transfer into Balb/c mice. At higher concentrations both VOCs induced oxidative stress demonstrated by increased isoprostane and glutathione-S-transferase-pi1 protein levels in the lung of non-sensitized mice. Treatment of PVC flooring-exposed mice with N-acetylcysteine prevented the VOC-induced increase of airway inflammation.</p> <h3>Conclusions</h3><p>Our results demonstrate that exposure to VOCs may increase the allergic immune response by interfering with DC function and by inducing oxidative stress and has therefore to be considerate as risk factor for the development of allergic diseases.</p> </div

NMP and TXIB induce oxidative stress <i>in vitro</i> and <i>in vivo.</i>

<p>A549 human lung epithelial cells were exposed to NMP or TXIB for 24 h. Expression of GSTP-1 was quantified by western blotting (A). Naïve mice were exposed to NMP or TXIB on two consecutive days for 6 hours, lung tissues were taken and GSTP-1 expression was quantified by western blotting (B) and 8-isoprostane (C) was measured as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0039817#pone.0039817.s003" target="_blank">File S1</a>. In the pseudoimages, the blue to red coloring represents the lowest to the highest light intensity in NMP (52 µg/m³)- or TXIB (31 µg/m³)-exposed NFκB/luciferase transgenic mice (D). Photon emission was quantified over the lung area (arrow) as mean fold of induction (E). Data are expressed as mean ± SEM from three independent experiments (A), n ≥ 9 animals per group (B, C) or <i>n</i> = 4 per group (D, E); *<i>p</i><0.05 <i>vs</i>. CON.</p

Increased acute allergic immune response by PVC flooring is abrogated by the antioxidant NAC.

<p>Treatment of Balb/c mice with NAC (1g/l) during exposure to PVC flooring reduced the enhanced acute airway inflammation (A), the number of eosinophils in the BAL fluid (B), OVA-specific IgE levels (C), IL-13 and IL-5 cytokine levels (D) and the production of 8-isoprostane in lung homogenates (E) compared to NAC-untreated mice. Data are expressed as mean ± SEM, n ≥ 9 animals per group; *<i>P</i><0.05, PVC flooring <i>vs.</i> OVA; ^#P<0.05, PVC flooring <i>vs</i>. PVC flooring + NAC.</p

Exposure to PVC flooring increases acute airway inflammation, antigen-specific IgE and Th2 cytokine levels and reduced IFN-γ production in OVA-sensitized Balb/c mice.

<p>Balb/c mice were immunized with OVA (day 1 and 14) and then challenged with OVA on days 14 and 17–19. Mice were exposed to PVC flooring from day 0 to day 20. Effect of PVC flooring on inflammation (H&E, x200, A), verified by an objective, investigator-independent computer-based quantification of lung inflammation (B), on total cell numbers in the BAL fluid (C), OVA-specific IgE levels (D), lung resistance (E), lung compliance (F) and Th2 cytokine levels in the supernatant of OVA-re-stimulated splenocytes (G) or mediastinal lymphnodes (H). Data are expressed as mean ± SEM, n ≥ 9 animals per group; *<i>p</i><0.05 <i>vs</i>. OVA.</p