Effects of interferon gamma and dexamethasone on serum IL-4 and SP-A in rat model of pulmoanry fibrosis

Objective To explore the effect of interferon gamma (IFN-γ) and dexamethasone and their possible underline mechanisms on the development of pulmonry fibrosis induced by bleomycin in rats. Methods One hundred and twenty rats were randomly divided into 4 groups: normal control group, pulmonary fibrosis group, IFN-γ treated group and dexamethasone treated group. On 1, 3, 7, 14 and 28 days after bolemycin treatment, 6 rats were killed and the lungs and serum were collected for histopathologic with electron microscope. Interleukin-4 (IL-4) and surfactant protein A (SP-A) were detected by ELISA and Western Blotting respectively. Results The degrees of fibrosis, the level of IL-4 and SP-A decreased significantly in IFN-γ group and dexamethasone group compared with the pulmonary fibrosis group(P0.01). Conclusion IFN-γ and dexamethasone have the inhibitory effect on the process of pulmonary fibrosis. IFN-γ's mechanisms maybe relate to balancing cytokine and decreasing lung injury.