Effects Of Astragaloside IV On Airway Inflammation And Airway Remodeling In Chronic Asthma Model Mice And Its Mechanism

The effect of astragaloside IV on airway inflammation and remodelling in a murine model of chronic asthmaObjective:To observe the influence of astragaloside IV on airway inflammation and remodelling in a murine model of chronic asthma. Methods: 48 female BALB/c mice are randomly divided into four groups. They are control group, OVA group, astragaloside IV group and Budesonide group. Every group contained 12 mice. Ovalbumin (OVA)-sensitized mice were chronically challenged with aerosolized 1%OVA for 30 min/day, 3 days/ week for 8 weeks. Mice in the astragaloside IV group were intragastrically administered with astragaloside IV (50mg/kg) daily for 8 consecutive weeks. Mice in the budesonide group were exposed to an aerosol of budesonide daily during the period of OVA challenge. airway responsiveness to acetylcholine chloride was measured with AniRes 2005 animal lung function analysis systems 24 hours after the last OVA challenge. The sections were stained with either hematoxylin & eosin to assess the inflammatory cell infiltrates, periodic acid schiff (PAS) to quantify airway global cells and Masson's trichrome to determine collagen deposition in the lungs. Total collagen content of the lung was determined by hydroxyproline assay. Tinterleukin (IL)-4?IL-13 and VEGF levels in bronchoalveolar lavage fluid (BALF), and total immunoglobulin E (IgE) levels in serum were measured by ELISA.The expression of?-SMA?VEGF and TGF-?1 in lungs were evaluated by immunohistochemistry.The protein expression of TSLP were determined by western blot. The mRNA of TGF-?1 and TSLP were measured by real time PCR.Results: The airway resistance in the OVA group was obviously increased in a dose-dependent manner by administration of ACh, whereas only a slight increase could be detected in the control group. There were no significant differences in baseline airway resistance among the four groups (P>0?.05). The airway resistance generated by administration of ACh at doses from 30 to 270 mg/kg increased significantly in the OVA group compared with the control group (P<0?.01). Treatment with astragaloside IV or budesonide led to a sharp decrease in airway resistance compared with the OVA group (P<0?.05). There were no significant differences in airway resistance between the astragaloside IV group and budesonide group (P>0?.05). The number of eosinophils and total inflammatory cells in BALF in the OVA group increased significantly compared with the control group (P<0.01). Treatment with astragaloside IV or budesonide significantly decreased the number of eosinophils and total inflammatory cells in BALF (P< 0.05). There were no significant differences in the number of eosinophils and total inflammatory cells in BALF between the astragaloside IV group and budesonide group (P>0?.05). The levels of the Th2 cytokines IL-4 and IL-13 in BALF and total serum IgE were significantly increased in OVA-sensitized/challenged mice comapred with the control group (P<0.01). Daily administration of astragaloside IV or budesonide reduced the levels of these Th2 cytokine in BALF and total serum IgE compared with the OVA group (P<0?.05). There were no significant differences in the levels of BALF IL-4 and IL-13 and total serum IgE between the astragaloside IV group and budesonide group (P>0?.05). A significant increase in the number of PAS-positive epithelial cells was found in the OVA group compared with the negative control group (P<0.01). Treatment with astragaloside IV or budesonide reduced the number of PAS-positive cells (P<0.05). The mean area of Masson's trichrome staining (collagen deposition) in the OVA group was significantly enhanced compared with the negative control group (P<0.01). Administration of astragaloside IV or budesonide caused a marked reduction in collagen deposition compared with the OVA group (P<0.05). Total lung hydroxyproline content in the OVA group was significantly greater than that in the control group (P<0.01). In contrast, treatment with astragaloside IV or budesonide significantly reduced total lung hydroxyproline content compared with the OVA group (P<0.05).The area of the?-SMA-stained smooth muscle layer in OVA- sensitized and challenged mice was significantly greater than that in the saline-treated control (P<0.01). Administration of astragaloside IV or budesonide decreased the?-SMA immunostained area compared with the OVA group (P<0.05).The mRNA and protein levels of TGF-?1 and TSLP in the lungs in the OVA group increased significantly compared with that in the control group (P<0.05). Treatment with astragaloside IV or budesonide decreased the mRNA and protein levels of TGF-?1 and TSLP compared with that in the OVA group (P<0.05). The protein levels of VEGF in the lung and BALF in the OVA group was significantly enhanced compared with the negative control group (P<0.01), Administration of astragaloside IV or budesonide decreased the VEGF protein levels compared with the OVA group (P<0.05). Conclusion: Astragaloside IV alleviate the airway inflammation, AHR and airway remodelling in a murine model of chronic asthma , by down-regulating the expression levels of VEGF , TGF-?1 and TSLP.Part twoThe effect of astragaloside IV on the expression of TSLP in A549 cellsAbstract:Objective To investigate the effect of astragaloside IV on the expression of TSLP mRNA in A549 cells, and to explore whether nuclear factor?B (NF-?B) is involved. Methods:A549 cells were cultured with cytokines,TNF-?and IL-4, the expression of TSLP mRNA at 4 h?10h and 18h were detected by real time–PCR. At 4 h, the effect of astragaloside IV,or PDTC (NF-?B inhibitor ) on the expression of TSLP mRNA were also quantified by real time–PCR. The cytoplasm protein expression of I?B?was evaluate by western blot and the nuclear translocation of NF-?B P65P was detected by immunofluorescence assays at 0.5h and 1h, respectively.Results: Compared with the control group, the expression of TSLP mRNA was significantly increased in A549 cells stimulated with TNF-?and IL-4 at 4h, and decreased at 10h, almost reduced to the baseline at 18h. PDTC greatly inhibited the level of TSLP mRNA . Astragaloside IV had little inhibitory effects on the expression of TSLP mRNA. However, Astragaloside IV suppressed the nuclear translocation of NF-?B P65, enhanced the protein level of I?B?in the cytoplasm. Conclusions: NF-?B pathway may play an important role in regulating TNF-?and IL-4 stimulated TSLP mRNA expression. Astragaloside IV suppressed the nuclear translocation of NF-?B P65, enhanced the protein level of I?B-?in the cytoplasm. But, Astragaloside IV had little inhibitory effects on the expression of TSLP mRNA.