Study on the Therapeutical effect of astragaloside IV on bleomycin-induced lung fibrosis in rats

OBJECTIVE To investigate the therapeutical effect of astragaloside IV (AS-IV) on bleomycin- induced lung fibrosis in rats. METHODS 24 SD rats were randomly divided into four groups: normal control group, bleomycin group, AS-IV early treatment group and late treatment group. Rats were instilled intratracheally with bleomycin (5mg / kg) or saline on the first day and AS-IV was oral administrated with 1ml per day from day 2 (early) and day 14 (late). All rats were killed, and the lung tissues were collected on the 28th day. Masson staining and Ashcroft scoring were performed to assess the level of lung fibrosis. The hydroxyproline contents in lung tissues were measured by alkaline hydrolization. ELISA was used to assess the expression of fibrotic cytokines (TGF-β1 and TNF-α) in lung tissues. RESULTS Bleomycin significantly induced lung fibrosis in rats. Early treatment with AS-IV could significantly improve the BLM-induced lung fibrosis, decrease hydroxyproline contents in lung tissues and downregulate TGF-β1 and TNF-α expression in lung tissues (P﹤0.05). However, late treatment with AS-IV could not alleviate BLM-induced lung fibrosis. CONCLUSION AS-IV may has no therapeutical effect on advanced lung fibrosis.