柠檬苦素对哮喘幼年大鼠气道炎症的影响OA

Objective:To investigate the effect of limonin(LIM)on airway inflammation in young rats with asthma by regulating CCL2-CCR2 signaling pathway.Methods:Young SD rats were induced with ovalbumin to establish an asthma model,and randomly divided into model group,low-dose LIM group,high-dose LIM group,dexamethasone group,AAV-NC group,high-dose LIM+AAV-CCL2 group and high-dose LIM+RS102895 group,with 10 rats in each group.Another 10 young SD rats were taken as control group.After grouping and intervention treatment,asthma symptoms and lung function of rats were evaluated,and their asthma scores,peak expiratory flow(PEF),and forced expiratory volume in 0.3 seconds(FEV0.3)/forced vital capacity(FVC)were compared.Inflammatory cells in bronchoalveolar lavage fluid(BALF)were classified and counted by Giemsa staining.HE staining was applied to detect patho-logical morphology of lung tissue,and their airway inflammation scores were compared.ELISA was applied to measure levels of IL-5,IL-6,IL-13 and TNF-α in BALF and serum.Flow cytometry was used to detect proportions of Th1 and Th2 cells in spleen and lung tissues.Western blot was applied to detect expressions of CCL2 and CCR2 proteins in lung tissues.Molecular docking of LIM with CCL2 protein was performed.Results:Compared with model group,asthma score,airway inflammation score,numbers of eosinophils,mac-rophages and lymphocytes,levels of IL-5,IL-6,IL-13,TNF-α,IL-4,proportion of Th2 cells,and expressions of CCL2 and CCR2 proteins were reduced in low-dose and high-dose LIM groups and dexamethasone group,while IFN-γ level,PEF and FEV0.3/FVC,proportion of Th1 cells were increased,and the changes in various indicators were greater in high-dose LIM group and dexamethasone group(P<0.05),there was no statistically significant difference in each index between high-dose LIM group and dexamethasone group(P>0.05).Compared with high-dose LIM group,all the quantitative indicators in high-dose LIM+AAV-CCL2 group showed an oppo-site trend(P<0.05),and the quantitative indicators in high-dose LIM+RS102895 group further decreased or increased(P<0.05).Binding energy of LIM and CCL2 after molecular docking was-7.03 kcal/mol,and the binding activity was good.Conclusion:LIM may inhibit expressions and release of inflammatory cytokines by blocking the activation of CCL2-CCR2 signaling pathway,thereby reducing airway inflammation and improving lung function in young rats with asthma.