Effect Of Imperatorin On Airway Inflammation In Asthmatic Mice Through P38MAPK/NF-?B Pathway

OBJECTIVE:To observe the effect of imperatorin on airway inflammation in mice models of bronchial asthma and to explore whether its possible mechanism is related to the p38MAPK/NF-?B signaling pathway.METHODS:Fifty clean grade BALB/c male mice were randomly divided into 5 groups,10 in each group:normal group,ovalbumin asthma model group,imperatorin low dose group,imperatorin high dose group,and dexamethasone positive control group.OVA-induced asthma models were established and treated with 30 mg/kg and 10 mg/kg imperatorin and 0.5 mg/kg dexamethasone respectively,and the control group was replaced with saline.The bronchoalveolar lavage fluid was centrifuged 24 h after the last challenge,and the sediment after centrifugation was made into a cell suspension.After cell smear,Diff-Quik staining was performed to count and classify the cells.The supernatant after BALF centrifugation was used to detect the content of IL-4,IL-5 and IL-13 in the supernatant by ELISA;The left lung tissue sections of mice were stained with HE and Masson to observe their pathological changes.The content of NF-?B p65 in lung tissue was observed by immunohistochemical staining.The right lung tissue of mice was taken and BCA was quantified after protein extraction,then western blot was performed to detect the content of p-p38MAPK and NF-?B p65.RESULTS:The results of Dif-Quick staining and statistical analysis showed that the total number of cells,neutrophils,eosinophils,and lymphocytes in BALF of the asthma model group were significantly higher than those in the control group,and compared with the normal control group,there was a significant difference(P<0.05);the total number of cells,neutrophil,eosinophils and lymphocytes in BALF of mice treated with imperatorin and dexamethasone were significantly lower than those in the model group(P<0.05).The levels of IL-4,IL-5 and IL-13 in BALF of asthma modcl group were significantly higher than those in control group by ELISA(P<0.05);The levels of IL-4,IL-5 and IL-13 after treatment with imperatorin were significantly lower than those in the model group(P<0.05).The lung tissues of mice were observed by HE and Masson staining.Compared with the normal group,the mice in the model group had wider submucosa,destructed tracheal wall and alveoli,increased infiltration of inflammatory cells in the alveolar space and interstitium and deposition of collagen fibers around the airway.After the treatment of imperatorin and dexamethasone,the bronchus and lung tissue injury was significantly reduced compared with the model group.The expression of NF-xBp65 in lung tissue of mice was observed by immunohistochemical staining.The results showed that compared with the normal control group,there were more brown positive cells around the bronchi in normal group;After treatment with imperatorin and dexamethasone,the number of positive cells around the bronchi were significantly reduced compared with the model group.Western Blot showed that the contents of p-p38MAPK and NF-?B p65 in lung tissues of the model group were significantly higher than those in the control group(P<0.05).The protein contents of p-p38MAPK and NF-?B p65 in the lung tissues of the mice treated with imperatorin and dexamethasone were decreased(P<0.05).CONCLUSIONS:Imperatorin can reduce the levels of IL-4,IL-5,and IL-13,thus inhibiting airway inflammatory cell infiltration and collagen deposition in asthmatic mice and exerting a role in inhibiting airway inflammation.The mechanism of action may be achieved by regulating the p38MAPK/NF-?B signaling pathway.