Traffic Related PM_2.5 And Its Water-soluble Components Regulate Airway Fibrosis Through The TGF-?1/SMAD3 Signaling Pathway In Asthmatic Rats

Objective:To observe whether PM_2.5.5 and its water-soluble components cause airway fibrosis in asthmatic rats,whether TGF-?1/SMAD3 signaling pathway may play a role.Methods:70 SD male rats were randomly divided into 7 groups:NS group,Asthma group?OVA group?;PM_2.5.5 suspension group(PM_2.5.5 group);PM_2.5.5 water-soluble components low?WSL group?;PM_2.5.5 water-soluble components high?WSH group?;PM_2.5.5 water-soluble components high+SB431542 group?WSH+SB group?;PM_2.5.5 water-soluble components high+SIS3 HCI?WSH+SI group?.Except for NS group with NS injection,the other groups by intraperitoneal injection of OVA and aluminum hydroxide mixed suspension sensitization,and NS group with normal saline atomized excitation,the rest groups with3%OVA aerosol inhalation inspiring,asthma rats model was constructed,after PM_2.5.5 and its water soluble component exposure 4 times,half rats were scarified?exposed four times?,when PM_2.5.5 and its water soluble component exposure 8 times,the rest half rats were sacrified?exposed eight times?,all rats were collected bronchoalveolar lavage fluid?BALF?.HE staining was used to observe the pathological changes of pulmonary and bronchial inflammation in rats.Masson staining was used to observe the fibrosis of the rat lung bronchial.The expression level of IL-6,HO-1,NOX-4 in the plasma was determined by enzyme-linked immunosorbent assay?ELISA?.Real-time fluorescence quantitative polymerase chain reaction?qRT-PCR?was used to determine the expression level of TGF-?1,SMAD3,CTGF,COL?gene in lung tissue.The levels of TGF-?1,SMAD3,HO-1,IL-6 protein in lung tissues were determined by Western blot.Immunohistochemistry?IHC? was used to detect the positive expression level of TGF-?1,SMAD3,CTGF,COL?protein in lung bronchial of rats.Results:1.In the rats exposed four times,the spleen organ coefficient in OVA group was higher than that in NS group?P<0.05?,and that in WSH group was higher than that in OVA group?P<0.05?.In the rats exposed four times,the coefficient of spleen organ in the OVA group was higher than that in the NS group;compared with the OVA group,the coefficient of spleen organ of the PM_2.5.5 group increased?P<0.05?,and the WSH+SB group was lower than that in the WSH group?P<0.05?.Left lung viscera coefficient in OVA group is higher than NS group,WSH+SB group is lower than WSH group?P<0.05?.2.The total numbers of cells,neutrophilic?GRA%?,eosinophils?EOS%?,lymphocytes?LYM%?in BALF in the OVA group were higher than that in the NS group,and the total numbers of cells,GRA%,EOS%,LYM%in the WSL group and the WSH group were higher than that in the OVA group.The total numbers of cells,GRA%,EOS%,LYM%in the WSH+SB group and the WSH+SI group were lower than that in the WSH group.3.The levels of IL-6 and NOX-4 in the plasma of the rats rats exposed eight times of OVA group was higher than that of the NS group?P<0.05?,and the level of HO-1 was lower than that of the NS group?P<0.05?.The levels of plasma IL-6 and NOX-4 in the PM_2.5.5 group and the WSH group and the WSL group were higher than those in the OVA group?P<0.05?,and the levels of HO-1 were lower than those in the OVA group?P<0.05?.Plasma IL-6 and NOX-4 in WSH+SB group and WSH+SI group was lower than that in WSH group?P<0.05?,and HO-1 was higher than that in WSH group?P<0.05?.4.The scores of lung inflammation and fibrosis in the OVA group were higher than those in the NS group?P<0.05?.The scores of lung tissue inflammation and fibrosis in the WSL group and the WSH group were higher than those in the OVA group?P<0.05?.The scores of pulmonary inflammation and fibrosis in WSH+SB group and WSH+SI group were lower than that in WSH group?P<0.05?.5.The contents of TGF-?1,SMAD3,IL-6 protein?Western blot?in the lung tissues of the rat OVA group were higher than that of the NS group?P<0.05?,and the content of HO-1 protein was lower than that of the NS group?P<0.05?.The contents of TGF-?1,SMAD3,IL-6 protein in the lung tissues of WSL group and WSH group were higher than that of OVA group?P<0.05?,and HO-1 protein content was lower than that of group B group?P<0.05?.TGF-?1,SMAD3,IL-6 protein content in lung tissues of WSH+SB group and WSH+SI group was lower than that of WSH group?P<0.05?,and HO-1 protein content was higher than that of WSH group?P<0.05?.6.The expressions of TGF-?1,SMAD3,CTGF and COL?mRNA?qRT-PCR?in the lung tissues of the rat OVA group was higher than that of the NS group?P<0.05?.The expressions of TGF-?1,SMAD3,CTGF and COL?mRNA in the lung tissues of WSL group and WSH group were higher than those of OVA group?P<0.05?.Expression levels of TGF-?1,SMAD3,CTGF and COL?mRNA in lung tissues of WSH+SB group and WSH+SI group were lower than that of WSH group?P<0.05?.7.The expressions of TGF-?1,SMAD3,CTGF and COL?positive protein?IHC?in the lung tissues of the rat OVA group were higher than that of the NS group?P<0.05?.The expressions of TGF-?1,SMAD3,CTGF and COL?positive proteins in lung tissues of WSL group and WSH group were higher than that of OVA group?P<0.05?.Expressions of TGF-?1,SMAD3,CTGF and COL?positive proteins in lung tissues of WSH+SB group and WSH+SI group were lower than that of WSH group?P<0.05?.Conclusion:PM_2.5.5 and its water-soluble components can activate TGF-?1/SMAD3 signaling pathway to regulate airway fibrosis by up-regulating fibrogenic factors CTGF and COL?as well as the oxidative stress factor NOX-4 and the inflammatory factor IL-6,and down-regulating the anti-inflammatory antioxidant factor HO-1in asthmatic rats.