Effects Of PM2.5 On The Levels Of IL-17 And HDAC2 In Mouse Pulmonary Macrophage Strain

Objective:Chronic obstructive pulmonary disease(COPD)is associated with chronic inflammation affecting predominantly the lung parenchyma and peripheral airways that results in largely irreversible and progressive airflow limitation.This inflammation is characterized by increased numbers of alveolar macrophages,neutrophilsT lymphocytes(predominantly TC1,TH1,and TH17 cells),and innate lymphoid cells recruited from the circulation.Particle aerodynamic equivalent diameter less than or equal to 2.5?m,also known as fine particles,it is a part of the total suspended particulate matter(TSP),which belongs to the air pollutants with important hygiene significance.Fine particles can absorb a large amount of toxic and harmful substances,easily lead to respiratory tract injury by entering deep respiratory tract.Pulmonary macrophage is an important defense barrier in the respiratory tract,which can swallow foreign particles and remove of foreign bacteria,when lung macrophages damaged,will release a large number of cytokines,increase the incidence and mortality of respiratory diseases.COPD causes increasing global health problems,new biological markers for COPD prediction and prognosis are urgently necessary.In this study,fine particulate matter-PM2.5 was used to stimulate mouse pulmonary macrophage,and the changes of IL-17 and HDAC2 were observed to explore the role of PM2.5 in the pathogenesis of the disease,to investigate if Interleukin 17,(IL-17)and Histone deacetylase2(HDAC2)levels can be used as promising,easily detected biomarkers.Methods:1 The concentration of IL-17 in cell supernatant was measured byELISA method.Cultured RAW264.7 cells line,adjusting the cell concentration to5×106/ml,In 24 well polystyrene tissue culture plates and incubated overnight.Groups were divided as follows:(1)Control group: added the same volume of serum-free medium 1640 with the experimental group,incubated cells.(2)LPS group:LPS,the final concentration of 100ng/ml,added the culture medium,icubated cell.(3)PM 2.5 25ug/ml group: PM 2.5,the final concentration of 25ug/ml,in addition to the culture medium,incubated cell.(4)PM 2.5 50ug/ml group: PM 2.5,the final concentration of 50ug/ml,in addition to the culture medium,incubated cell.(5)PM 2.5 100ug/ml group: PM 2.5,the final concentration of 100ug/ml,in addition to the culture medium,incubated cell.(6)PM 2.5 200ug/ml group: PM 2.5,the final conce-ntration of 200ug/ml,in addition to the culture medium,incubated cell.All groups were stimulated for 12 h,cell supernatant was collected,stored at-80?,and IL-17 was detected by ELISA method.2 Quantitative determination of HDAC2 activity in cells by HDAC2 colorimetric assay.The experiment was carried out according to the above groups to stimulate the raw264.7,and the HDAC2 activity was measured by colorimetry.Results:1 The change of IL-17 levels in cell supernatant: Compared with the negative control group,the content of IL-17 in the supernatant of raw264.7 cells increased after LPS Stimulation,PM2.5 stimulated raw246.7 cells and the content of IL-17 increased;PM2.5 concentration of 50ug/ml group,the highest content of IL-17,IL-17 content in PM2.5 100ug/ml,200ug/ml group was lower than PM2.5 concentration in 50ug/ml group,but higher than the negative control group,the difference was statistically significant(P<0.05);There was no significant difference in PM2.5 concentration between 50ug/ml group and 100ug/ml group.2 Quantitative determination of HDAC2 activity by 2 colorimetric assay: Compared with the negative control group,after LPS stimulation of raw264.7 cells,the activity of HDAC2 decreased.PM2.5 stimulated raw264.7 cells,the activity of HDAC2 decreased,and with the increase of PM2.5 concentration,HDAC2 activity was significantly reduced(P< 0.05).Conclusions:1 PM2.5 can stimulate raw246.7 cells in two way,lower concentration stimulation increased secretion of IL-17,suggest that IL-17 is involved in the development of cell injury.There was no significant difference the concentration of IL-17 in PM2.5 concentration between 50ug/ml group and 100ug/ml group.T he concentration of IL-17 in PM2.5 200ug/ml group decreased,the results indicated that high concentration of PM2.5 could decrease the cell viability.2 LPS and PM2.5 induced histone acetylation enhanced after stimulating raw264.7 cells,resulting in high expression of pr-oinflammatory cytokinesIL-17,and promoting inflammation.