GAMMA-LINOLENIC ACID-CONTAINING DIET ATTENUATES BLEOMYCIN-INDUCED LUNG FIBROSIS IN HAMSTERS

Although bleomycin (BLM), an antineoplastic drug, is used in the treat ment of a variety of tumors, the mechanism(s) that contribute to its i nduced lung injury and fibrosis are not fully elucidated. Since altera tions in the levels of certain fatty acid metabolites have been associ ated with BLM-induced lung injury, we tested the effects of dietary ga mma-linolenic acid (GLA)-containing evening primrose oil on BLM-induce d morphological alterations in the hamster lung, the marked elevation of tissue hydroxyproline (a marker for collagen synthesis), and elevat ed generation of arachidonic acid metabolites (marker of inflammatory mediators). Our data revealed that after 14 d of dietary CLA-containin g oil (i) BLM-induced elevation of lung hydroxyproline was suppressed (P < 0.05), (ii) the marked BLM-induced elevation of lung leukotriene B-4 (LTB4) (a marker of polymorphonuclear generation of proinflammator y LTB4) was significantly suppressed (P < 0.05). The decrease in LTB4 was accompanied by marked elevations (P < 0.05) of lung prostaglandin E-1 (PCE1) and 15-hydroxyeicosatrienoic acid (15-HETrE), both with kno wn antiinflammatory properties. Taken together, data from these studie s suggest that dietary GLA-containing oil contributes to tissue elevat ion of PCE1 and 15-HETrE, which in vivo may attenuate lung inflammatio n and fibrosis.