The Influence Of Atmospheric Fine Particulate Matter (PM_2.5) On Mast Cells Secreting Beta Aminocaproic Glycosidase,histamine And IL-4

Objectives:There is a large amount of fine particulate matter（particulate matter,PM）in the atmosphere,which is mostly removed by the mucosa after inhaling.PM_2.5 is the main component of atmospheric particles,which is less than or equal to 2.5 μm,after inhalation into the lungs,83% deposited in the lungs.PM_2.5 can penetrate into the lung ventilation area,through the respiratory barrier into the circulatory system,spread to the whole body.It’s large surface area is favored by toxic compounds such as metal ions and polycyclic aromatic hydrocarbons（PAHs）.In recent years,environment factors,especially PM_2.5 on cardiovascular disease and respiratory disease are increasingly affected.A large number of studies have shown that exposure to PM_2.5 can have a serious impact on human health and induce related diseases.Some studies have shown that PM_2.5 is significantly associated with respiratory disease and mortality in cardiovascular disease.More and more scholars are concerned about the relationship between PM_2.5 and allergic diseases.Epidemiological studies have demonstrated the relationship between allergic diseases and atmospheric fine particles and suggest that atmospheric fine particulate stimulation is a factor in the increased prevalence of asthma.Diesel exhaust particles（DEPs）,it’s main components are smaller than 2.5μm,have been shown to be involved in the development of allergic airway inflammation.Their target cells include epithelial cells,B lymphocytes,T lymphocytes,macrophages and mast cells.Mast cells are one of the most important effector cells that mediate allergy,and the IgE receptor on the mast cell surface is cross-linked with the IgE antibody that binds the allergen,which can cause the downstream signal cascade to cause the mast cell degranulation and produce inflammatory cells factor,which in turn mediates allergic reactions.Methods:In our study,PM_2.5 on human mast cell line LAD2 related biological detection,to explore the biological effects of PM_2.5 on mast cells and the possible mechanism.Objective to explore the biological effect of atmospheric fine particulate matter（particulate matter,PM）PM_2.5 on mast cells.With the intelligent traffic total suspended particulate air sampler to collect PM_2.5 in the industrial zone of Chongqing city,and by mixed suspension of PM_2.5 in different concentrations acting on LAD2 cell.The experiment is divided into three parts:（1）cell counting kit-8（CCK-8）was used to detect the activity of mast cells;（2）microplate method was used to detect mast cells releasing the beta aminocaproic glycosidase;ELISA method was used to detect mast cells releasing histamine and interleukin 4（interleukin-4,IL-4）level;（3）the levels of reactive oxygen species（reactive oxygen species,ROS）were measured by ELISA to explore the possible mechanism of PM_2.5 on mast cells.Results:1.After the PM_2.5 of final concentration of 12.5-25 μg/mL stimulating mast cells,the activity of LAD2 cells increased gradually with the increase of PM 2.5 concentration,and the cell viability was the highest when PM_2.5（25 μg/mL）was on LAD2 cells.With the increase of PM_2.5（50-800μg/mL）,the activity of LAD2 cells decreased.2.After the PM_2.5 of final concentration of 25 μg/mL stimulating mast cells,the concentration of the supernatant of beta aminocaproic glycosidase,histamine and IL-4 that LAD2 cells secreted and released were 23.78 ± 3.98%,12.32 ± 0.18 μg/mL,267.63 ± 7.97 pg/mL;the baseline secretion of beta aminocaproic glycosidase,histamine and IL-4 were 14.05 ± 1.12%,9.72 ± 0.23 μg/mL,154.25± 7.71 pg/mL;the former three were significantly higher than baseline（p < 0.01）.3.The ROS levels that PM_2.5（12.5-100μg/m L）stimulated LAD2 cells to produce gradually increased,and after PM_2.5 of the final concentration of 25μg/mL stimulated mast cells,the ROS level that LAD2 cells generate was 7.99 ± 0.29 ng/mL,higher than the baseline（5.88 ± 0.49 ng/mL）,and both significantly different（p < 0.01）.Conclusion:Our study confirms that low concentrations of PM_2.5（12.5-25μg/mL）may have a stimulating effect on LAD2 cells.As the concentration increase,PM_2.5 may cause toxic effects on mast cells,causing cell death or inactivation.PM_2.5 may make LAD2 cells generate ROS through oxidative stress,and thus mast cells produce cytokines and inflammatory factors.