Mechanism Study of Soufeng Yuchuan Formula on Regulating Airway Remodeling in Asthmatic Rats Based on Epithelial-Mesenchymal Transformation
Objective To explore the mechanism of Suofeng Yuchuan Formula on inhibiting airway remodeling in asthma by regulating epithelial-mesenchymal transformation(EMT).Methods Sixty rats were randomly divided into normal control group,model control group,Dexamethasone group,high-,medium-and low-dose groups of Soufeng Yuchuan Formula,with 10 rats in each group.In addition to the normal control group,the other groups were injected and inhaled with ovalbumin(OVA)to replicate the asthma rat model.The rats in each group were killed after 21 days of administration of the corresponding drug.Hematoxylin-eosin(HE)staining was used to observe the pathological changes of lung tissue.The ultrastructure of epithelial cells in rat lung was observed by transmission electron microscope.The contents of transforming growth factor β1(TGF-β1)and interleukin-17(IL-17)in serum were detected by enzyme-linked immunosorbent assay(ELISA).Real-time fluorescence quantitative polymerase chain reaction(RT-PCR)was used to detect mRNA expressions of TGF-β1,α-smooth muscle actin(α-SMA),E-cadherin and N-cadherin in lung homogenate.Protein expression levels of TGF-β1,α-SMA,E-cadherin and N-cadherin in lung tissue were detected by Western Blot.Results Compared with the normal control group,the serum contents of TGF-β1 and IL-17 in the model control group were significantly increased(P<0.01).The mRNA and protein expressions of TGF-β1,α-SMA and N-cadherin in lung tissues were significantly up-regulated(P<0.01),while the mRNA and protein expressions of E-cadherin were significantly down-regulated(P<0.01).HE staining showed thickening of airway wall and alveolar wall,and a large number of inflammatory cells infiltrated in the visual field,and the inflammation score was significantly increased(P<0.01).Transmission electron microscopy showed that the epithelial cells of lung tissue had severe edema.Local dissolution and thinning of intracellular matrix,and obvious swelling of organelles were observed.Compared with model control group,the contents of TGF-β1 and IL-17 in serum of dexamethasone group and all doses of Soufeng Yuchuan Formula groups were significantly decreased(P<0.05,P<0.01).The mRNA and protein expressions of TGF-β1,α-SMA and N-cadherin were significantly down-regulated(P<0.05,P<0.01),while the mRNA and protein expressions of E-cadherin were significantly up-regulated(P<0.05,P<0.01).The inflammatory cell infiltration of lung tissue and thickening of bronchial wall and alveolar wall were found to be reduced.The inflammation score of dexamethasone group and high-dose group of Suofeng Yuchuan Formula was reduced(P<0.05).Ultrastructure showed that the degree of edema of epithelial cells was significantly reduced,the cell membrane was intact,the intracellular matrix was uniform,and most of the organelles were slightly swollen.Conclusion Soufeng Yuchuan Formula can reduce the level of TGF-β1,thereby improve EMT in lung tissue,and achieve the purpose of preventing and treating airway remodeling in asthma.