| ObjectivesA large number of epidemiological studies indicate that exposure to air polltants can induce and exacerbate asthma symptoms, but the exact mechanism is completely unclear. The evidence from in vitro and animal experiments suggest that inflammation, oxidative stress and the pathway of IgE expression and regulation are involved in this process. There is still no sufficient evidence of from population studies. The aim of this study was to assess the exposure to indoor and outdoor air polltants of asthma chindren in Beijing, and to expore the effects of air pollution on airway inflammation,oxidative stress and signal pathway of IgE expression and regulation.Methods1. Sixty male asthma children aged 5-14 living in Beijing were selected. The general information on age, medication using, home decoration, passive smoking and so on was investigated by questionnaire.2. The air pollution exposure levels were assessed by both indoor and outdoor air monitoring. The indoor concentrations of benzene, toluene,xylene were determined by thermal desorption-gas chromatography. The concentrations of formaldehyde were determined by AHMT spectrophotometric method. The concentrations of PM2.5 and black carbon were determined by gravimetric method and multi-wavelength absorption method respectively. The data on ambient air pollutant concentration of PM2.5, PM10, NO2 and SO2 was collected from the air quality publishing platform of Beijing Environmental Protection Monitoring Center.3. As the biomarkers of airway inflammation, the exhaled nitric oxide (FeNO)and exhaled breath condensate (EBC) pH were determined by electrochemical method and micro-electrode potential analysis method respectively.4. As the biomarker of airway oxidative stress, 8-isoprostane in exhaled breath condensate (EB(C 8-ISO) was determined by LC-MS/MS method.The levels of EB(C 8-ISO were adjusted by EBC urea which was also determined by LC-MS/MS method.5. The signaling molecules related to the pathway of IgE expression and regulation in peripheral blood serum were measured to explore the trigering action of air pollution on IgE. The signaling molecules were determined by ELISA kit.6. Stratified analysis and multiple linear regression model were used to control for confounding factors and comprehensive analyze triggering effect of air pollution on children asthma.Results1. The average concentrations of indoor PM2.5, BC,formaldehyde, benzene,toluene,m, p- xylene and o-xylene were 55.3 ± 29.9 ?g/m3, 3.8 ± 1.4 ?g/m3,62.2 ± 42.7 ?g/m3, 13.1 ± 15.9 ?g/m3, 18.7 ± 16.7 ?g/m3, 7.9 ± 7.9 ?g/m3 and 3.1 ± 5.0 ?g/m3 respectively, while the 7 days weighted average concentrations of outdoor PM2.5, PM10, SO2 and NO2 were 101.3 ± 87.6?g/m3,152.8 ± 88.4?g/m3,48.6 ± 39.8 ?g/m3 and 63.1 ± 27.7pg/m3 respectively. During the same periods, the indoor/outdoor ratio for PM2 5 concentration was 0.86 ± 0.39 (P25-P75: 0.62-1.01).2. After adjusting for confound factors such as age, asthma type, season and so on,the outdoor PM2.5, SO2,NO2 as well as indoor benzene were all significantly positive correlated with FeNO for all the subjects. When considering the subjects not using ICS only, the relationships between FeNO and outdoor PM2.5 and NO2 were still significant.3. After adjusting for confound factors such as age, asthma type, season and so on, for all the subjects, the outdoor N02 was significantly positive correlated with EBC pH for all the subjects. However, after stratified by ICS using, the relationship was significant for only subjects using ICS.4. After adjusting for confound factors such as age, asthma type, season and so on, no significant relationships between EBC 8-ISO and indoor or outdoor air polltants.5. The significant positive correlation between FeNO and EBC 8-ISO indicated that airway inflammation and oxidative stress are closely related.6. The signaling molecules within the two pathway involved in IgE expression and regulation in peripheral blood serum were correlated with each other.After adjusting for confound factors such as age, asthma type, season and so on, no effect of any air polltant on the levels of the molecules were detected.ConclusionThe results from indoor and outdoor air pollutants monitoring indicated that asthma children in Beijing were exposed to high level of air pollutants. And the exposure could cause or exacerbate respiratory inflammation. The using of ICS medications can control and reduce airway inflammation caused by air pollutants. The signaling molecules in serum related to the pathway of IgE expression and regulation may not be sensitive biomarkers for the study the triggering action of air pollution on childhood asthma. |
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