ABSTRACT
Objective To investigate the effects of alcohol extract of bark and male flower of Eucommia ulmoides Oliv. on airway allergic inflammation induced by chicken ovalbumin (OVA) in mice; To explore its mechanism of action. Methods On day 0, day 7, mice were intraperitoneally injected OVA for sensitization, followed by nasal stimulation for 21 days to establish airway allergic inflammation mice models. The mice were divided into normal group, model group, alcohol extract of bark of Eucommia ulmoides Oliv. group, alcohol extract of male flower of Eucommia ulmoides Oliv.group,and Dexamethasone group.Each medication group was given relevant medicine for gavage. The lung tissue was embedded in HE and PAS dyeing, to observe the pathological changes of bronchus and surrounding lung. The levels of serum OVA-IgE, IL-4, IFN-γ and IL-13 were measured by ELISA. The expression of ICAM-1, VEGF, MMP9 and TIMP1 were detected by immunohistochemistry. Flow cytometry was used to detect the expression of Th17 cells in peripheral blood. The expressions of TNF-α and IL-6 mRNA in lung tissue were detected by RT-PCR. Results The model group showed changes of airway allergic inflammatory such as eosinophils and other inflammatory cell infiltration, bronchial spasm, and mucus secretion. Lung histopathology in alcohol extract of bark and male flower of Eucommia ulmoides Oliv.groups was improved significantly(P<0.05).Compared with the normal group, the levels of serum OVA-IgE, IL-4 and IL-13 increased in model group, while the level of IFN-γ decreased (P<0.05, P<0.01). The expressions of ICAM-1, VEGF and MMP9 increased, while the expression of TIMP1 decreased (P<0.01); peripheral blood IL-17+cells increased (P<0.01); the expressions of TNF-α and IL-6 mRNA increased. Compared with the model group, the levels of serum OVA-IgE, IL-4 and IL-13 decreased in alcohol extract of bark and male flower of Eucommia ulmoides Oliv. groups (P<0.05, P<0.01); the expressions of ICAM-1 and VEGF decreased (P<0.05, P<0.01); the expression of TIMP1 increased. Alcohol extract of bark and male flower of Eucommia ulmoides Oliv.could down-regulate IL-17+cells,reduce the expression of IL-6 mRNA(P<0.05,P<0.01). Alcohol extract of bark of Eucommia ulmoides Oliv. group could induce the secretion of IFN-γ (P<0.01), and down-regulate the expression of TNF-α mRNA(P<0.05).Alcohol extract of male flower of Eucommia ulmoides Oliv. group could significantly down-regulate the expression of MMP9 (P<0.05). Conclusion Alcohol extract of bark and male flower of Eucommia ulmoides Oliv.can induce the production of OVA-IgE,inhibit secretion of Th2 cytokines, inhibit the expression of adhesion molecules, depress Th17 cells, so as to inhibit the airway allergic inflammation.
ABSTRACT
[Objective] To investigate the effects of airway dysbacteriosis on the development of murine atlergic airway diseases (AAD).[Methods] Female C57BL/6 mice were neubulized with Vancomycin for 10 days and then were sacrificed.The bacterial population in bronchoalveolar lavage fluid (BALF) were evaluated using 16S rRNA high-throughput sequencing technology,exploriug the method of establishing an airway dysbacteriosis mouse model.After the mouse model was established successfully,airway dysbacteriosis mouse models were established by the same method,and based on that,the mice were sensitized and challenged with ovalbumin (OVA) to induce airway allergic inflammation.The frequency of nasal rubbing behaviors per mice was counted;the total cell number and eosinophil relative abundance in BALF were evaluated;the lung tissue inflammation and goblet cell metaplasia were assessed according to histopathological features;and the IgE level in serum,IFN-γ,IL-4 and IL-5 levels in BALF,and IL-33 levels in serum,BALF and intestine tissue were measured by ELISA.[Results] Nebulization of Vancomycin increased Bradyrhizobium,Sphingopyxis,Cupriavidus,Pelomonas,and decreased Akkermansia and Prevotella_6 in airway,inducing significant airway dysbacteriosis.Using the animal model,further study found that airway dysbacteriosis exacerbated OVA-induced airway allergic inflammation,including increased nasal rubbing frequency,higher serun IgE level,more total cell count especially eosinophil infiltration,more serious lung tissue inflammation and goblet cell metaplasia.Additionally,compared to OVA group,mice in Dysbacteriosis and OVA group had significantly increased level of Th2 cytokine IL-4 and IL-5,and significantly decreased Thl cytokine IFN-γin BALF,which revealed that mice in Dysbacteriosis and OVA group had mote remarkable Thl/Th2 imbalance.Furthermore,IL-33 level showed a significant increase in BALF,but didn't change in serum or intestine tissue in Dysbacteriosis and OVA group compared to OVA group.Indicating that airway dysbacteriosis may only affect the local production of IL-33.[Conclusions] An airway dysbacteriosis mouse model was established by Vancomycin nebulization successfully.Airway dysbacteriosis may activate innate lymphoid cells (ILC) and Th2 cell by inducing local IL-33 secreting,which leads to the imbalance of Th1/Th2,and in turn promotes the development of AAD.