Objective To evaluate the effects of two different epidermal growth factor receptor tyrosine kinase inhibitors ( EGFR-TKIs) , Gefitinib and Erlotinib, on lung fibrosis induced by bleomycin.Methods Forty BALB/c female mice were randomly divided into four groups, ie. a control group( saline given orally and intratracheally) , a fibrosis group( saline given orally with bleomycin instillation) , a Gefitnib group( Gefitnib 20 mg/kg given orally with bleomycin instillation) , and an Erlotinib group ( Erlotinib25 mg/kg given orally with bleomycin instillation) . Bleomycin ( 3 mg/kg) was intratracheally instilled on the first day. Gefitinib or Erlotinib was given orally daily and normal saline as control. Then they were sacrificed by abdominal aortic bleeding 14 days after the bleomycin instillation. The left lung was stained with HE and Masson’s trichrome staining respectively for pathological examination. Total EGFR and phosphorylated EGFR were detected by immunohistochemistry. Hydroxyproline ( HYP) assay was performed in the right lung.Results Both Gefitinib and Erlotinib significantly reduced lung collagen accumulation and the content of HYP. Immunohistochemistry revealed that phosphorylation of EGFR in lung mesenchymal cells induced by bleomycin was inhibited. Furthermore, there was no difference between Gefitinib and Erlotinib in inhibiting lung fibrosis. Conclusion Our findings suggest that, in the preclinical setting, EGFR-TKIs may have aprotective effect on lung fibrosis induced by bleomycin.
Objective To investigate the expression of fibroblast activation protein( FAP) in mouse pulmonary fibrosis and the relationship between FAP and trarisforming growth factor β1 ( TGF-β1 ) .Methods The mouse model with pulmonary fibrosis was established by intratracheally instillation of bleomycin. The expressions of FAP, α-smooth muscle action( α-SMA) , and TGF-β1 in lung tissues were detected with immunohistochemical technique. Results There was no expression of FAP in the normal lung tissue. In the pulmonary fibrosis mice, FAP was found in the fibroblasts existed in bronchiolar adventitia or peribronchiolar ( and perivascular) connective tissue. In the fibroblast foci, the localizations of α-SMA, TGF-β1 , and FAP were similar, but the expression of FAP was more extensive than that of α-SMA and ber than that ofTGF-β1 . The degree of lung fibrosis was bly correlated with FAP, α-SMA, and TGF-β1 ( r = 0. 795,0. 766,0. 628; P lt; 0. 01) . A significantly positive correlation was also observed between TGF-β1 and FAP( r =0. 706, P lt; 0. 01) . Conclusions FAP is especially expressed in the fibroblast foci in pulmonaryfibrosis and bly correlated with the severity of pulmonary fibrosis. FAP and TGF-β1 possibly play a synergistic role in the progression of pulmonary fibrosis.