Suppressive effect of interferon γ on IL-13-induced fibrosis in fibroblasts

AIM：To investigate the suppressive effect of interferon γ (IFN-γ) on fibrosis induced by interleukin 13 (IL-13) in fibroblasts. METHODS：The fibroblasts were divided into IFN-γ (4×105U/L) group, IL-13 (100 μg/L) group, IFN-γ+IL-13 group and blank control group. At 24 h, 48 h and 72 h, the secreted collagen from fibroblasts was measured by hydroxyproline release assay. The mRNA expression of collagen type I α1 (Col1A1) in fibroblasts was examined by RT-PCR. The protein level of collagen type I synthesized in fibroblasts was analyzed by Western blotting. RESULTS：IFN-γ at 4×105U/ L significantly inhibited the proliferation of fibroblasts and down-regulated Col1A1 mRNA and cellular collagen. The mRNA expression of Col1A1 and the protein level of collagen type I in IFN-γ group were lower than those in blank control group at 48 h and 72 h. At 72 h, the mRNA expression of Col1A1 and the protein level of collagen type I in IL-13 group were substantially higher than those in blank control group, those in IFN-γ + IL-13 group were remarkable lower than those in blank control group, and those in IFN-γ group were also lower than those in blank control group. CONCLUSION：IFN-γ inhibits the fibrotic effect of IL-13 in fibroblasts.