| Objective:To observe the effects of NLRP3 inhibitor MCC950 intervention Th17/Treg on the airway inflammation in a mouse model of allergic asthma,to explore the role and mechanism of NLRP3 inflammasome-mediated mediated of Th17/Treg imbalance in the airway inflammation of asthma.Methods:Forty female BALB/c mice of SPF grade,aged 6-8-week-old were randomly divided into 5 groups:control group（NS）,asthma group（AS）,MCC950 low dose group（ML）,MCC950 high dose group（MH）and dexamethasone group（Dex）（n=8）.AS group was injected intraperitoneally with 10%ovalbumin（OVA）and calmogastrin saline suspension combined with subcutaneous injection on days 1 and 13,and stimulated with atomizing 10%OVA on days 19 to 23 for 30 minutes once a day.NS group was sensitized with PBS instead of the OVA and calmogastrin saline suspension and stimulated with normal saline instead of OVA.ML group was injected intraperitoneally with MCC95010 mg/kg 30 minutes on days 19,21 and 23 before atomization inhalation,MH group and Dex group were injected intraperitoneally with MCC950 10 mg/kg and 2mg/kg dexamethasone 30 minutes before each atomization inhalation respectively,and the remaining treatment was the same as that of AS group.Each group of mice were anaesthetized,bloodletting at 24-hour after the last stimulation,prepared bronchoalveolar lavage fluid（BALF）and Lung tissue specimens;and the total cell numbers,the white blood cell numbers and classifications were counted in bronchoalveolar lavage fluid（BALF）,and the concentration of IL-17A、IL-1β、IL-10、IL-18、IL-33、IL-35 were determined by ELISA,peripheral blood,lung and spleen tissues were collected to make mononuclear cell suspension,the proportion of CD4 cells IL-17（CD4+IL-17+）and CD4+CD25+CD127lowin CD4+cells,which reflected respectively the levels of T helper 17 cells（Th17）and regulatory T cells（Treg）,were measured by flow cytometry;the pathological changes of lung tissue were observed by HE staining,AB-PAS staining,and Masson staining paraffin sections of the lung tissue;the levels of NLRP3,Caspase-1 and TGF-β1 in lung tissue were observed by immunohistochemistry（IHC）.Results:Compared with the NS group,the total cell count,white blood cell count,percentage of eosinophil,and the concentrations of IL-17A,IL-1β,IL-18and IL-33 in BALF were increased in the AS group（P<0.01）,while the concentrations of IL-10 and IL-35 in BALF decreased（P<0.05）,and the proportion of Th17 cells in peripheral blood,lung and spleen tissues increased（P<0.01）,while the proportion of Treg cells decreased（P<0.01）,inflammatory cell infiltration score around the airway,airway mucus positive relative staining area,deposition area of airway collagen fiber,and the levels of NLRP3,caspase-1 and TGF-β1 protein all increased in lung tissue（P<0.01）.Compared with the AS group,the total number of BALF cells,white blood cell count,percentage of eosinophil,and the concentration of IL-17A,IL-1β,IL-18 and IL-33 decreased in the ML,MH and Dex groups（P<0.01）,and the concentration of IL-10,IL-35 increased（P<0.05）;The concentration of IL-35 in BALF of ML group was not significantly different from that of AS group（P>0.05）;compared with the AS group,in the ML,MH and Dex groups,the proportion of Th17 cells in peripheral blood,lung and spleen tissues decreased（P<0.01）,the proportion of Treg cells increased（P<0.01）,inflammatory cell infiltration score around the airway,airway mucus positive relative staining area,deposition area of airway collagen fiber,and the levels of NLRP3,caspase-1 and TGF-β1 protein all decreased in lung tissue（P<0.01）.Conclusion:（1）MCC950 can regulate Th17/Treg balance by down-regulating Th17function and up-regulating Treg function in asthmatic mice,reduce the levels of IL-17A,IL-1β,IL-18,IL-33,NLRP3,Caspase-1 and TGF-β1,increase the levels of IL-10,IL-35 in bronchial lung tissue,and reduce the airway inflammation in asthma.（2）NLRP3 inflammasome mediates the imbalance of Th17/Treg,participating in or aggravating the occurrence of the airway inflammation in asthma. |
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