Dexamethasone reduces serum level of IL-17 in Bleomycin-A5-induced rats model of pulmonary fibrosis.

BACKGROUND: Pulmonary fibrosis is a chronic progressive disease with limited therapeutic options and inflammatory cytokines play important roles in the pathogenesis of pulmonary fibrosis.

MATERIAL AND METHOD: Here, we investigated the changes of TGF-β1, IL-8, and IL-17 in the serum of bleomycin-A5-induced rats model of pulmonary fibrosis. 120 healthy male Wistar rats were randomly divided into three groups, the control group (n = 30), the model group (n = 45) and the dexamethasone (DEX) group (n = 45). The rats of both model group and DEX group were injected with Bleomycin-A5 (5 mg/kg) through tracheofistulization to induce pulmonary fibrosis, while the rats of the control group were injected with equivalent physiological saline. After operation, DEX (4 mg/kg) was given to the DEX group rats intraperitoneally once a day. Equivalent saline was administered to rats of both the control group and the model group.

RESULTS: On the 1st, 14th, and 28th day after operation, pathological changes of the lung tissues, and the levels of serum IL-8, TGF-β1, and IL-17 were measured. The concentrations of serum TGF-β1, IL-8, and IL-17 were significantly increased after bleomycin-A5 treatment, especially on the 14th day (p < .01). There was no significant difference between model group and DEX group in the serum level of TGF-β1 and IL-8, but DEX treatment significantly reduce serum IL-17 level (p < .01).

CONCLUSIONS: DEX protect bleomycin-A5-induced pulmonary fibrosis in rats through reduced the level of IL-17 in serum.