[Effects of vitamin E deficiency on bleomycin-induced pulmonary fibrosis in hamsters]

We examined the effect of free radicals on lung defense mechanism in bleomycin (BLM)-induced pulmonary fibrosis in hamsters. The concentration of vitamin E (VE) in the lung tissue increased significantly after intratracheal BLM administration. VE deficient hamsters showed increased lipid peroxide values in the lung tissue at a very early stage after BLM treatment. This was followed by decreased superoxide dismutase activities in the lung tissue. The results indicate that; 1) VE appears to be necessary for the prevention of lipid peroxidation in BLM-induced oxidant lung injury, 2) VE deficiency produces a large number of free radicals at the early stage after BLM treatment, and might induce protease-antiprotease imbalance within the lung, which probably causes an emphysematous change in the BLM-treated lung at a late stage after BLM administration.