Effect Of Triptolide On Airway Inflammation In Asthmatic Mice Through CXCL10/CXCR3 Axis

Objective:To explore the inhibitory effect of triptolide on airway inflammation in asthmatic mice through CXCL10/CXCR3 axis,and to provide a new theoretical basis for the treatment of asthma.Methods:Thirty-six healthy female Balb/c mice were randomly divided into control group,asthma model group and triptolide intervention group,with12 mice in each group.Asthma group and triptolide intervention group were sensitized by intraperitoneal injection of 0.2 m L ovalbumin(OVA)+ aluminum hydroxide suspension on the 1st,8th and 15 th day,while the control group was intraperitoneal injected with the same amount of normal saline at the same time.On the 22nd-35 th day,three groups of mice were placed in closed cartons respectively.Asthma model group and triptolide intervention group were atomized with 10 m L OVA solution for 30 minutes,and the cartons were shaken every 2 minutes to prevent the mice from piling up and interfering with the atomization effect.In the control group,the same amount of normal saline was atomized at the same time,and the carton was shaken every 2 minutes.The intervention group received intraperitoneal injection of triptolide 0.2m L with a dose of 40μg/kg one hour before each atomization excitation,and the asthma model group and control group received intraperitoneal injection of normal saline 0.2ml.Twenty-four hours after the last atomization excitation,three groups of experimental mice were killed by cervical dislocation method and marked.The right lung bronchoalveolar lavage fluid(BALF)of three groups of mice was collected respectively,and the inflammatory cells in BALF of three groups of mice were counted by Wright Giemsa staining.The levels of interleukin-4(IL-4),interleukin-5(IL-5),interleukin-10(IL-10),interleukin-13(IL-13),interleukin-17(IL-17)and tumor necrosis factor(TNF-α)in BALF of three groups of mice were detected by ELISA.The left lung tissues of three groups of mice were taken,and the morphological changes of bronchial tissues were observed by HE staining,and the changes of airway mucus hypersecretion were observed by PAS staining.Immunohistochemical staining and Western blot were used to detect the expression levels of CXCL10 and CXCR3 proteins in bronchopulmonary tissues.Results:1.Behavioral changes of the three groups of mice: the mental state,respiratory rate,weight change,eating and drinking behavior of the mice in the control group were normal;Asthma group mice showed signs of listlessness,increased respiratory rate,anorexia and aversion to drinking.The mental state,respiratory rate,weight change,eating and drinking behavior of mice in the intervention group were less than those in the asthma model group.2.Histomorphological changes of bronchus and lung: ⑴HE staining: The airway epithelial cells and smooth muscle of control mice were normal,and no inflammatory cells infiltrated;In the model group,a large number of necrotic epithelial cells,mucosal edema and a large number of inflammatory cells infiltrated in the airway of mice.The above pathological changes of mice in triptolide intervention group were less than those in asthma model group.⑵PAS staining: No mucus secretion was found in the airway of control mice;In the model group,a large amount of mucus was formed in the airway of mice,and goblet cells proliferated.The mucus secretion and goblet cell proliferation in airway of mice in triptolide intervention group were less than those in asthma model group.3.BALF detection indicators: ⑴ Compared with asthma model group,the total number of cells in BALF of mice in triptolide intervention group(28.6±3.85 vs 9.06±1.56),eosinophils(6.64±1.16 vs 2.64± 0.85),neutrophils(4.74±1.28 vs1.61±0.96),IL-4(66.31±4.43 vs 39.46±2.16),IL-5(81.29± 5.69 vs55.53± 2.64),IL-13(60.57±3.59 vs 39.17±1.23)and IL-17(70.03±3.61 vs42.96± 3.61)、 TNF-α(73.19±5.87 vs 41.29±4.83)in BALF of mice in the intervention group However,IL-10(13.92±1.38 vs 15.81±1.03)increased with statistical significance(P<0.05).4.Western blot results: The expression of CXCR3 and CXCL10 protein in bronchial lung tissue of mice in asthma model group is higher than that of normal control group,while that of CXCR3 and CXCL10 protein in triptolide intervention group is lower than that in asthma model group,with statistical significance(P<0.05).5.Immunohistochemical results: The expression of CXCR3 and CXCL10 in the airway of mice in the normal control group was less,while the expression of CXCR3 and CXCL10 protein in the airway of mice in the asthma model group was increased,mainly expressed in airway epithelial cells and mast cells.CXCR3 and CXCL10 protein expression was reduced in the triptolide intervention group compared to the asthma group.The relative expression levels were(30.25±3.56 vs 13.99±2.17),(36.82±1.92 vs 25.37.±2.13),respectively,and the difference was statistically significant(P<0.05).Conclusion:1.Triptolide can improve airway inflammation and inhibit the infiltration of inflammatory cells in the airway of asthmatic mice.2.Triptolide can up-regulate the expression of anti-inflammatory factors and down-regulate the expression of pro-inflammatory factors.3.Triptolide inhibits the expression of CXCL10/CXCR3 axis,which may be one of the mechanisms of inhibiting airway inflammation in asthmatic mice.