Curative effect of interferon gamma on pulmonary fibrosis in rats and the mechanisms

Objective To study the effects of interferon gamma (IFN-γ) on pulmonary fibrosis induced by bleomycin in rats and the related mechanisms. Methods A total of 90 rats were randomly divided into 3 groups (n=30 in each group): normal control group, pulmonary fibrosis group, and IFN-γ treated group. On days 1, 3, 7, 14, and 28 after bolemycin treatment, 6 rats in each group were sacrificed. PO 2 was determined. The lungs and serum were collected for histopathological and electron microscopic examinations. The contents of transforming growth factor β 1 (TGF-β 1) and fibronectin (FN) were determined by immunohistochemistry, and the contents of IL-4 and surfactant protein A (SP-A) were detected by ELISA and Western blotting, respectively. Results PO 2 level increased significantly (P0.01). The degrees of fibrosis, the levels of TGF-β 1 and FN, and the levels of IL-4 and SP-A decreased significantly in IFN-γ group as compared with those in the pulmonary fibrosis group (P0.01). Conclusion IFN-γ has the inhibitory effect on pulmonary fibrosis induced by bleomycin possibly through decreasing TGF-β 1 and FN expressions, regulating unbalanced T cytokines, and attenuating lung injuries.