The Effects Of Dingchuan Decoction On Neutrophilic Asthma And Its Mechanism

Objective:To explore the effect and mechanism of Dingchuan decoction(DCD)on mice model of neutrophilic Asthma.Methods:42 female C57BL/6 mice were randomly divided i nto normal control group(C group),neutrophilic asthma model g roup(group NA),low dose DCD group(DCD-L group),medium dose DCD group(DCD-M group)and high dose DCD group(DCD-H grou p)and dexamethasone group(DEX group).There are 7 mice in eac h group.The model group and all of the treatment groups mice wer e immunized subcutaneously with 20?g of grade V chicken egg O VA in 25?l PBS,emulsified in 75?l CFA on the 1 day,and all mi ce were exposed to aerosols consisting of 0.1%of Grade III OVA in PBS on the 22 and 23 day in order to induce acute exacerbatio n symptoms of asthma,The control group was sensitized and challe nged with PBS.The mice in each group were interfered before 3 ho urs of challenge.The normal control group and the model group m ice were given the same amount of saline or PBS.The Dingchuan decoction treatment groups were given 16.5,33 and 66g�kg~-11 Dingch uan decoction differently.0.001g�kg-1dexamethasone solution was gi ven to the DEX group by intraperitoneally injections.All mice wer e killed for analysis 24 h after the last challenge.To evaluate the as thma model according to the changes of mice symptoms during the aerosols exposure and the pathological changes of the bronchiole.by hematoxylin and eosin stain.As well as comparing the changes of airway resistance,total number and percentage of leukocytes in blood and brochial alveolar lavage fiuid(BALF).Then,neutrophils o f each group were separated from blood,the apoptosis rate ofneutrop hils was detected by flow cytometry.The migration rate of neutrop hils was detected by transwell experiment.ELISA was used to dete ct the expression levels of IL-17 in the bronchial alveolar lavage su pernatant.Results:(1)Symptoms of the mice of groups during the aerosols exposure:Except to the C group mice,the mice of other groups show different degrees of asthma-like symptoms during the OVA challenge.The degree of symptoms is lighter in the three DCD groups than the NA model group,but the degree of DCD-M group is the lightest.The severity of symptoms between the Dex group and the NA group has no significant difference.(2)The histopathological examination of lung tissue in each group:the C group showed that the bronchial,alveolar and lung tissues were intact and the infiltration of inflammatory cells were less.The NA group showed that typical pathological changes,such as bronchial stenosis,luminal mucosal folds hyperplasia,epithelial cell shedding,swelling and visible mucus plug,alveolar and lung tissue structure destruction,and a large number of inflammatory cells infiltrated surrounding the bronchial and vascular,the neutrophils and lymphocytes infiltration was the most obvious.Lung tissue structure destruction and bronchial mucosal edema and infiltration of inflammatory cells in the DCD treatment groups were significantly improved compared with NA group,and the treatment of the DCD-M group was the best.The DEX group showed no obvious changes compared to the NA group.(3)The results of the airway resistance in each group:the airway resistance of the mice in the NA model group was significantly increased with the increasing of the concentration of methacholine(MCH),which were significantly higher than the C group(P<0.01)in different concentrations of methacholine challenge.The airway resistance level of the mice in the three DCD groups was lower than witch of the NA group(P<0.01);The airway resistance level of the DCD-M group and the DCD-H group were lower than witch of the DCD-L group(P<0.05),but there was no significant difference between the DCD-M group and the DCD-H group(P>0.05).the NA group and the DEX group have no significant differences in the airway resistance level(P>0.05).(4)The total number of cells and classified count of cells in BALF of mice in each group:compared with the C group,the total cell number of leukocytes and NEU%of the NA group were significant higher(P<0.01).Compared with the NA group,the above datas were significant decreased in the three DCD groups(P<0.01).The above datas in DCD-M Group and the DCD-H group were lower than the DCD-L group,but there were no statistical differences between the DCD-M group and DCD-H group(P>0.05).There was no statistical difference between the NA group and the DEX group(P>0.05).(5)The peripheral differential count of white blood cells in mice:the NEU%in peripheral blood of the NA model group were significantly higher than those in the C group(P<0.01).The NEU%of the three DCD groups were lower than the NA group(P<0.01).The NEU%in DCD-H group and in DCD-M group were lower than the DCD-L group(P<0.01),but there was no statistical difference between the DCD-M group and the DCD-H group(P>0.05).There was no statistical difference between the NA group and the DEX group(P>0.05).(6)The neutrophils apoptosis rate in all groups:Compared with the C group,the neutrophils apoptosis rate of the NA model group was declined(P<0.01).the neutrophils apoptosis rate of the three DCD groups were higher than the NA group(P<0.01).Compared with the DCD-L group,the neutrophils apoptosis rate in DCD-M group and in DCD-H group were increased(P<0.01),but there was no statistical difference between the DCD-M group and the DCD-H group(P>0.05).There was no significant difference between the DEX group and the NA group(P>0.05).(7)The neutrophils migration rate in all groups:Compared with the C group,the neutrophils migration rate of the NA model group was declined(P<0.01).Compared with the NA model group,The neutrophils migration rate of the three DCD groups were significantly declined(P<0.01);Compared with the DCD-L group,the neutrophils migration rate in DCD-M group and in DCD-H group were declined(P<0.01),but there was no significant difference between the DCD-M group and DCD-H group(P>0.05),There was no significant difference between the DEX group and the NA group(P>0.05).(8)The expression of IL-17 in the supernatant of BALF:Compared with the C group,IL-17 in BALF supernatant of the NA group was significantly increased(P<0.01).Compared with the NA group,The expression of IL-17 was decreased in the three DCD groups(P<0.01);Compared with DCD-L group,the expression of IL-17 in DCD-H group and in DCD-M group were declined(P<0.01),but there was no significant difference between the DCD-M group and DCD-H group(P>0.05).And there was no significant difference between the DEX group and the NA group(P>0.05).Conclusion:Dingchuan decoction may reduce neutrophil infiltration in the airway of neutrophilic asthma mice by inducing neutrophil apoptosis,inhibiting neutrophil migration and downregulating the expression of IL-17.