[Pulmonary fibrosis and antioxidant agents].

Lung inflammatory cells in idiopathic pulmonary fibrosis (IPF) is characterized by an increased spontaneous production of oxidants. This suggests that the oxidants may play a role in causing the epithelial cell injury in the early stage of IPF. Bleomycin (BLM) induces pulmonary fibrosis by oxidant production. We tested the hypothesis that a dietary supplement of vitamin E (VE) may protect against, and its deficiency may exacerbate, BLM-induced pulmonary fibrosis. Because the hamster is known to be the best model among animals studied mimicking human lung antioxidant enzyme activities, Syrian Golden hamsters were used in this study. In dietary VE supplement and BLM treated group (Ead.B), mean serum VE concentration increased by about 3 times that of control (C) and the BLM treated group (CB). Despite the remarkably high VE content, no significant difference was found between CB and Ead.B for pressure-volume (PV) curves and morphological data. In BLM treated with dietary VE deficient group (Ede.B), serum VE concentrations markedly decreased on all experimental days compared with other groups. Mechanical properties in P-V curves of Ede.B showed most less distensible characteristics in early stage and most distensible characteristics in later stage. These emphysematous changes observed in P-V curves in the later stage of Ede.B, coincided with the morphological observations. In the early stage of BLM treatment, lipid peroxide concentrations in the lung tissue were significantly higher in Ede.B compared with other groups. It was concluded that a dietary supplement of VE cannot protect against BLM-induced pulmonary fibrosis, and a dietary VE deficiency exacerbates BLM lung injury to produce on emphysema in the hamster.