Modulation of Bleomycin Lung Injury By Short Exposure to Hyperoxia

Abstract

n e w information about the initiation o f lung fibrosis induced by various fibrogenic agents. Glucocort icoids are used clinically in the t reatment of patients with pulmonary fibrosis. T h e s e corticosteroids have b e e n shown selectively to decrease procollagen synthesis in connect ive tissues and in fibroblasts.6 T h e b leomycin-medi ated increase o f collagen synthesis and collagen accumulation in rat lung is b locked by glucocorticoid t r e a t m e n t . 7 8 To d e t e r m i n e the molecular mechanism by which these drugs regulate collagen synthesis , chick skin and chick lung fibroblasts were treated with b leomycin followed by dexamethasone. This glucocorticoid reversed the b leomycininduced polysomal partit ioning o f type I procollagen m R N A and also reversed the stimulatory effect o f b leomycin on procollagen synthesis. T h e s e data indicate that glucocorticoids regulate col lagen synthesis induced b y b l e o m y c i n in lung and cultured fibroblasts.