The Effect Of PM_2.5 On Allergic Airway Inflammation In Mice

In recent years,various environmental problems caused by particulate pollution have become increasingly severe.Traffic sources,as one of the major contributors to atmospheric particulates,have also attracted more and more attention.Epidemiological studies have confirmed that high levels of environmental particulates and asthma are associated with increased proximity to traffic arteries and levels of air pollution.Fine particulates collected from busy road sections have been found to cause severe allergic airway inflammation.This article collects PM_2.5 at a certain intersection in Taiyuan to study its effect on OVA-induced allergic airway inflammation in mice,and to explore the mechanism of traffic source on the airway inflammation.1.In this study,the PM_2.5 collected at the busy traffic intersection in Taiyuan was selected and analyzed for chemical composition.The Hg and As elements in PM_2.5 were determined by cold atomic fluorescence spectrometry.Al,Ni,Pb,Zn,Cu,Cr,Fe and Si elements were measured by inductively coupled plasma chromatography.The content of elemental carbon and organic carbon was determined by carbon analyzer.The content of 16 kinds of polycyclic aromatic hydrocarbons such as naphthalene,phenanthrene,pyrene,benzopyreneandsoonweredeterminedbygas chromatography-mass spectrometry?GC-MS?.The results showed that the concentration of particulate matter in the PM_2.5 collection point of the traffic source was 78.01?29.06?g/m3,which exceeded the daily concentration limit set by the Chinese Government(24h PM_2.5<75?g/m³).Among the water-soluble inorganic ions in the transportation source PM_2.5,the three secondary ions SO₄^2-NO₃^-and NH₄⁺are the most abundant,and the inorganic elements are the important components in the particles,accounting for more than 20%of the particle concentration,among which Al,Si,and Fe are the most abundant element of the ten elements measured.The concentration of fluorene,fluoranthene,benzo[b]fluoranthene,benzo[a]pyrene,dibenzo[a,h]anthracene and benzo[g,h,i]anthracene in 16 kinds of PAHs were higher.And the concentration of benzo[a]pyrene exceeds the national standard daily average concentration limit of 0.0025?g/m³,the concentration of organic carbon?OC?is 13.21?g/m³ and elemental carbon The?EC?concentration is4.28?g/m³,and the ratio OC/EC>2 indicates the presence of secondary organic carbon.2.To investigate the effect of PM_2.5 exposure on allergic airway inflammation induced by OVA.The mice were randomly divided into four groups and treated with physiological saline,OVA,PM_2.5 and PM_2.5+OVA respectively.Lung tissue,bronchoalveolar lavage fluid?BALF?,and serum were analyzed for cellular inflammation,cytokines,and heme oxygenase-1?HO-1?expression.At the same time,the histopathological changes of lung in mice were observed.The results showed that the exposure of PM_2.5 and the allergenic protein OVA alone resulted in an increase in the total number of cells in the BALF,an increase in inflammatory cells,and an oxidative injury of the inflammatory factors IL-4,IL-17A in the BALF,serum and lung tissues.The increase of HO-1 content and mRNA expression of the marker and the histopathological results of lung support the above results.In the process of OVA-induced airway inflammation,the addition of PM_2.5.5 exposure increased the levels of inflammatory factors,HO-1,and mRNA expression,increased pathological changes,and significant changes in the structure of the lung tissue,airway and accompanied by a large number of inflammatory cells infiltration around the blood vessels.These results indicate that the traffic source PM_2.5 caused oxidative damage to the lungs and promoted allergic airway inflammation in mice induced by OVA.