Biol. Pharm. Bull. 27(5) 634—640 (2004)

group of disorders designated “lung diseases”, is characterized by fibroblast proliferation and extracellular matrix remodeling, resulting in severe respiratory impairment. Pulmonary fibrosis currently affects up to 100000 people in the U.S.A. Immunosuppressive therapy, the mainstay of the current approach to pulmonary fibrosis, is not particularly effective. Therefore the development of successful strategies to prevent pulmonary fibrosis remains an urgent challenge. The pulmonary fibrosis model in rodents induced by bleomycin (BLM) is widely used to study the mechanism of lung fibrosis and antifibrotic effects of numerous drugs. Following intratracheal administration into the lungs of rats, BLM causes alveolar cell damage, inflammatory response, fibroblast proliferation and subsequent collagen content deposition. Lesions observed in the early stages of lung damage induced by BLM resemble chronic human fibrotic lung disease, both histologically and physiologically. Interventions designed to limit the consequences of the inflammatory response [such as corticosteroids, anti-tumor necrosis factor (TNF)-a antibody, and anti-transforming growth factor (TGF)-b antibody] and to protect the lung from oxidant damage (such as Ginkgo biloba extract, metalloporphyrin, and N-acetylcysteine) are effective in suppressing BLM-induced pulmonary fibrosis. These findings suggest that inhibition of lung inflammation and lipid peroxidation may be employed as therapeutic strategies for pulmonary fibrosis in the clinic. Feitai, a composite formula comprising the herbs Huangqin (Radix of Scutellaria baicalensis GEORGI), Beishashen (Radix of Glehnia littoralis FR. SCHMIDT ex MIQ), Gualou (Fructus of Trichosanthes kirilowii MAXIM), Baibu [Radix of Stemona sessilifolia (MIQ.) MIQ], Pipaye [Folium of Eriobotrya japonica (THUNB.) LINDL] is traditionally used as a folk remedy in China for the treatment of patients with pulmonary tuberculosis. The major ingredient of Feitai is Huangqin. The beneficial components of Huangqin are flavonoids that have multiple biological activities, such as antiinflammatory, antibacterial, antiviral, antiallergic, immunestimulating, and antioxident properties. The other ingredients of Feitai also have some therapeutic effects, such as antiimflammatory, antibacterial, antitussive, and antipyretic effects. In the present study, we extensively investigated the effects of Feitai on BLM-induced pulmonary fibrosis in rats. Moreover, changes in biochemical and histopathologic parameters following BLM instillation are characterized to elucidate the role of Feitai during the development of pulmonary fibrosis.