The effect of deferoxamine on bleomycin-induced lung fibrosis in the hamster.

Bleomycin is a commonly used antineoplastic compound that can produce a dose- and time-dependent pneumonitis and fibrosis in humans. The mechanism of bleomycin-induced fibrosis is not known. However, current data suggest that the production of oxygen radicals by way of a ferrous ion-molecular oxygen mechanism might be related to the pulmonary fibrosis. Therefore, we evaluated the possibility that parenterally administered deferoxamine, an iron chelating compound, could modulate the morphologic and biochemical estimates of bleomycin-induced lung fibrosis in hamsters. Deferoxamine pretreatment and daily injection for 21 days after intratracheally administered bleomycin resulted in a 33% reduction in lung collagen accumulation compared with that after bleomycin treatment alone. However, fibrosis was still present in the bleomycin-deferoxamine group; the animals showed a 142 and 150% increase in lung collagen compared with that in saline- and deferoxamine-treated control animals, respectively. Morphologic estimates of the severity of fibrosis in the bleomycin-deferoxamine treatment group were reduced when compared with the bleomycin treatment group alone, but was increased compared with saline- and saline-deferoxamine-treated control animals. These data indicate that deferoxamine treatment reduces the severity of bleomycin-induced pulmonary fibrosis in hamsters. The mechanism might be by the prevention of iron-catalyzed, free-radical formation.