Inhibitory Effects Of Bilirubin On Bleomycin-Induced Pulmonary Fibrosis In Rats

Objective: The purpose of this study was to evaluate the suppressive effect of bilirubin in bleomycin-induced pulmonary fibrosis in rats. Methods: A single dose of bleomycin was intratracheal injected to induce pulmonary fibrosis of rats, consecutive changes of tumor necrosis factor a (TNF-a ), interleukin 6 (IL-6) and transforming growth factor β1 (TGF-β1)released by alveolar macrophages(AM) were measured with radioimmunoassay and immunohistochemical staining respectively. Superoxide dismatase (SOD) malondialdehyde (MDA)and total antioxidant capacity were observed with biochemical assay. Results:(1) Bilirubin significantly suppressed release of TNF-a , IL-6, TGF-β1 by AM, but remained higher than those of the control. (2) Bilirubin had protective effects on lipid peroxidution injury markedly increase the level of SOD as well as TAC decrease the level of MDA. Conclusion: (1) An oxidant/antioxidant imbalance might be one of the mechanisms of pulmonary fibrosis. (2) Bilirubin exerts somewhat inhibitory effects on the process of pulmonary fibrosis in animal model.