Expression of IL-17A in bleomycin-induced pulmonary fibrosis model

Objective To explore the expression of interleukin-17A(IL-17A) during pulmonary fibrosis. Methods Forty male C57BL/6 mice were randomized as normal control group(N group) and bleomycin-induced pulmonary fibrosis model group(BLM group) with 20 in each.Mice were administered with bleomycin intratracheally at a dose of 5 mg/kg in BLM group and intratracheally administered with 0.9% saline of the same dose in N group.Then they were sacrificed on days 3,7,14 and 28.IL-17A in lung tissues was measured by semi-quantitative RT PCR and immunohistochemisty.The number of CD4+IL-17+T cells in the spleen was measured by flow cytometry. Results ① IL-17A was located in the terminal bronchioles,respiratory bronchioles and alveolar epithelia.② IL-17A began to increase on day 7,reached the peak on day 14 and then began to decrease on day 28,which was all higher than in normal group. ③ The pattern of changed number of CD4+IL-17+T/CD4+T cells from spleen lymphocytes was the same as the amount of IL-17A expression. Conclusion The expression of IL-17A is up-regulated in bleomycin-induced pulmonary fibrosis in mice.IL-17A may be involved in the development and progression of pulmonary fibrosis.