ABSTRACT
<p><b>OBJECTIVE</b>To investigate the effects of interleukin-17 (IL-17) on the proliferation, transformation and collagen synthesis of the lung fibroblasts in mice with bleomycin-induced pulmonary fibrosis.</p><p><b>METHODS</b>In a mouse model of pulmonary fibrosis established by intratracheal administration of 5 mg/kg bleomycin, the dynamic expressions of IL-17/IL-17 receptor (IL-17R) mRNAs were detected by RT-PCR. At 14 days following bleomycin administration, the pulmonary fibroblasts were isolated, cultured and identified. MTT assay was used to assess the proliferation of the pulmonary fibroblasts in response to IL-17 treatment at different concentrations, and RT-PCR and Western blotting were employed to examine the mRNA and protein expressions of α-smooth muscle actin (α-SMA) and types I and III collagen.</p><p><b>RESULTS</b>IL-17/IL-17R mRNA levels were increased obviously in the pulmonary fibroblasts of rats with pulmonary fibrosis, and the highest expressions occurred at 14 days following bleomycin administration. Exogenous IL-17, at the optimal concentration of 50 ng/ml, significantly promoted the proliferation of the pulmonary fibroblasts in primary culture and obviously increased α-SMA expression and types I and III collagen synthesis in the fibroblasts.</p><p><b>CONCLUSION</b>IL-17 can promote the proliferation, transformation, and collagen synthesis of the pulmonary fibroblasts from rats with bleomycin-induced pulmonary fibrosis.</p>