[The role of oxygen radicals in bleomycin-induced pulmonary fibrosis].

A model of pulmonary fibrosis in rat has been developed using intratracheal administration of bleomycin (BLM) A5 (5mg/kg). Histopathologic features and total lung collagen were studied. We found that type I pneumocytes detached, basement membrane denuded and endothelia edema were the earliest changes in BLM induced pulmonary fibrosis. Serum MDA (an index of lipid peroxidation) level in rats receiving intratracheal bleomycin were increased at earlier time after bleomycin administration. Meanwhile, MDA level in the lung homogenate was elevated too. Our results indicated that the injured type I pneumocytes and endothelia caused by oxygen radicles are the fundamental damages in bleomycin-induced pulmonary fibrosis.