Experimental Study Of Glaucocalyxin A Alleviates OVA Induced Airway Inflammation In Asthmatic Mice Based On NF-κB/STAT3 Signaling Pathway

Objective:To investigate whether glaucocalyxin A(GLA)has an inhibitory effect on airway inflammation induced by OVA in asthmatic mouse models,and explore its possible mechanism.Method:Fifty female BALB/c mice were randomly divided into 5 groups:normal saline control group(SAL),asthma group(OVA),low dose group of glaucocalyxin A(GLA 20,the dose of 20 mg/kg),The high-dose group of glaucocalyxin A(GLA 40,the dose of 40 mg/kg)and the dexamethasone positive control group(DEX,the dose of 10 mg/kg).The mouse model of asthma was established by ovalbumin(OVA)induction method.On the 1st and 14th days,200 μL OVA solution were intraperitoneally injected to sensitize the mice.The mice of SAL group were intraperitoneal injected of equal volume of normal saline.From the 21st day,except for the mice in the SAL group,the mice in the other groups were challenged with 5%OVA solution and inhaled for 30 minutes every day for a week,and the corresponding dose of glaucocalyxin A was injected intraperitoneally 30 minutes before challenge.Twenty-four hours after the last challenge,whole body plethysmography method was used to measure airway hyperresponsiveness(AHR).Mice were anesthetized to death by ether,and bronchoalveolar lavage fluid(BALF)was obtained with cold saline and lung tissue was obtained.After centrifugation,the levels of Th2 cytokines IL-4,IL-5,IL-13 and Thl cytokines IFN-y in BALF supernatant were measured by ELISA.Diff-Quik staining was used to classify and count the inflammatory cells in BALF precipitates.After left lung embedding and sectioning,HE,Masson and PAS staining was performed to observe the effect of glaucocalyxin A on OVA-induced inflammatory response around the airway in asthmatic mice.The right lung tissue was homogenized to extract protein,and Western blot was used to determine the phosphorylation level of STAT3 and NF-κB in lung tissue.Results:Glaucocalyxin A can significantly inhibit the levels of Th2 cytokines IL-4,IL-5,and IL-13 in BALF induced by OVA,and increase the level of Th1 cytokines IFN-γ,the results are statistically different(P<0.05).In addition,it can reduce the total number of inflammatory cells in BALF and Number of various inflammatory cells,the results are statistically different(P<0.05).The pathological staining results showed that glaucocalyxin A can inhibit the infiltration of inflammatory cells in the lung tissue,inhibit the deposition of collagen in the airway,and reduce the secretion of airway mucus.Western blot results showed that glaucocalyxin A could inhibit the phosphorylation of NF-κB and STAT3 in lung tissue of OVA-induced mice.Conclusion:Glaucocalyxin A can inhibit inflammation in the lung of OVA-induced mice.The mechanism may be related to the inhibition of NF-κB and STAT3 phosphorylation.