Abstract: Objective: To evaluate the therapeutic effects and mechanism of Huayulifei on blemycin-induced pulmonary interstitial fibrosis in rats. Methods: Rats were randomly divided into four groups: the control group, the model group, the Huayulifei group and the hydrocortisone group. Pulmonary fibrosis was induced by blemycin(5mg/kg) in the Huayulifei and hydrocortisone groups, while 0.9% saline was given to the control group. At the second day, Huayulifei（oral, 13410mg/kg）was given to the Huayulifei group, intraperitoneal Hydrocortisone sodium succinate（25mg/kg）to the Hydrocortisone group, and oral saline to the control and model groups. Rats were killed at14 and 28 days after bleomycin. The lung was isolated and calculate the lung coefficients. Hematoxylin and eosin-staining, and expressions of TGF-β and Smad7 proteins were determined by the immunohistochemical technique. Results: Forty-four rats were involed in the analysis. ①:The airsacculitis and fibrosis of lungs were fairly severe and much deposition of the collagen fibers was found in the model group.There was little inflammatory cells, the alveoli structure was nearly normal, and most of the airsacculitis and fibrosis of lungs was mild in the Huayulifei group. The alleviation of airsacculitis and fibrosis of lung were not signficantly decreased in the hydrocortisone group. ② Expression of TGF-β protein was significantly lighter in the Huayulifei group than in the model and hydrocortisone groups; expression of Smad7 protein was significantly higher in the Huayulifei group than in the model and hydrocortisone groups. Conclusion: Huayulifei can ameliorate the blemycin-induced pulmonary fibrosis in rats probobly by improving the expression of Smad7 in lung tissues and decreasing the expression of TGF-β protein by feedback inhibition.

Key words: Pulmonary interstitial fibrosis, Huayulifei, Lung coefficients, Smad7 protein, Transforming growth factor beta