The effects of Astragalus on production of cytokines and ultrastructure in rat model of pulmoanry fibrosis

Objective:To observe the effect of Astragalus decoction and Astragalus saponins on the balance of T helper 1/T helper 2(Th1/Th2) cytokines,seral TNF-α,and the ultrastructure in BLM-induced pulmonary fibrosis rats,in order to explore its underlying mechanisms.Methods:Wistar rats were evenly randomized into normal,model,Astragalus decoction and Astragalus saponins groups,with dexamethasone as the control.Pulmonary fibrosis model was established by injection of Bleomycin(BLM) via trachea (5 mg/kg).After 24 h,the rats were given the drugs by ig in all groups once daily.At the 14 th day and 28 th day,6 rats were killed and the lungs were collected for observing the ultrastructure.Interleukin-4(IL-4),interferon gamma(IFN-γ) and tumor necrosis factor-α(TNF-α) of the sera were detected by enzyme linked immunosorbent assay(ELISA).Results:In comparison with those of normal group,IFN-γ contents were significantly lower,with IL-4 and TNF-α considerably higher in model group (P0.05).Compared with those of model group,IFN-γ contents were significantly higher(P0.05),and the level of both IL-4 and TNF-α was significantly lower(P0.05).No significant differences were found for the above parameters (P0.05) among the astragalus decoction,astragalus saponins and dexamethasone groups.Changes in ultrastructure of the model group revealed that the numbers of alveolar type Ⅱ epithelial cells decreased and microvilli on the surface of the cells were rare,and irregular nucli with nuclear chromatin agglutinated.In addition the inner lamellar bodies decreased,with vacuole-like changes.Most mitochondria were exhibited swelling.Fibroblast in alveolar liquid proliferated significantly and the collagen fibers increased.The degree of fibrosis was more mitigative in each treatment groups by microscope and ultrastructure.Conclusion:Astragalus decoction and astragalus saponins have inhibitory effects on the process of pulmonary fibrosis.The mechanisms maybe related to Th1/Th2 balancing and protection of lungs from injury.