Effects of astragalus polysaccharides on immune balance and the expression of nitric oxide in pulmonary fibrosis rats

Objective To observe the effects of astragalus polysaccharides on the balance of T helper1/T helper2(Th1/Th2) cytokines and the level of nitric oxide(NO) in Bleomycin(BLM)-induced pulmonary fibrosis rats,and to explore its underlying mechanisms.Methods Wistar rats were randomly divided into control,model,Dexamethasone,astragalus decoction and astragalus polysaccharides groups.Pulmonary fibrosis models were established by injection of BLM via trachea(5 mg/kg).After 24 h,rats were given drugs once daily.At 14 and 28 d,6 rats of each group were killed for detecting the levels of interleukin-4(IL-4),interferon gamma(IFN-γ),NO in the serum.Results In comparison with those in control group,the levels of IFN-γ and the ratio of IFN-γ/IL-4 were significantly decreased,while the levels of IL-4 and NO were increased and the degree of fibrosis was higher in model group(P0.01);whereas compared with those in model group,the levels of IFN-γ and the ratio of IFN-γ/IL-4 were significantly increased(P0.05,P0.01),except to astragalus polysaccharides group of 14 d, the level of NO was significantly lower in dexamethasone,astragalus decoction and astragalus polysaccharides groups(P0.05,P0.01).No significant differences were found between astragalus polysaccharides group,Astragalus decoction group and dexamethasone group in these indexes(P0.05).Conclusions Astragalus polysaccharides has the protective effect on the process of pulmonary fibrosis rats.Its mechanisms maybe relate to balancing cytokine,regulating the metabolism of nitric oxide.