Hepatocyte growth-promoting factor for rat bleomycin-induced pulmonary fibrosis

Objective To study the effect of hepatocyte growth-promoting factor(HGF) on bleomycin-induced pulmonary fibrosis in rats and its possible mechanism.Methods Pulmonary fibrosis was induced in Wistar rats by intratracheal instillation of bleomycin.Then the rats received daily hepatocyte growth-promoting factor 1mg/kg(group D),dexamethasone 3mg/kg(group C),or normal saline(group B).Seven rats in each group were sacrificed at 7d and 28d after intratracheal instillation.Histological changes of the lungs were evaluated by hematoxylin and eosin stain,Masson's trichrome stain.Collagen content of the lung tissue was assessed by hydroxyproline concentration.Expressions of TGF-β1,MMP-9,and TIMP-1 proteins in lung were assessed by immunohistochemistry.Results Hydroxyproline concentrations on 7d and 28d was 1.58±0.22 and 1.88±0.22mg/g in group D,1.87± 0.18 and 2.63±0.20mg/g in group B(P0.05,P0.01).The score of pulmonary fibrosis at 28d was 1.95±1.00 in group D,3.36±0.85 in group B(P0.05).The expression of TGF-β1 protein on 7d and 28d was 59.2±8.02 and 51.2±7.66 in group D,76.4±12.24 and 62.34.44±9.58 in group B(P0.05).The expression of TIMP-1 protein in group D at 7d and 28d was lower than that of group B(P0.05).The expression of MMP-9 protein in group D at 28d was more than that of group B(P0.05).Except the expression of MMP-9 protein,other results in group D were not significantly different from those in group C(P0.05).Conclusion pHGF alleviates bleomycin induced pulmonary fibrosis in rats.Inhibiting the expression of TGF-β1 and regulating the expression of MMP-9 and TIMP-1 in lung tissues may be one of the mechanisms.