Salvianolic acid B inhalation solution enhances antifibrotic and anticoagulant effects in a rat model of pulmonary fibrosis

The purpose of this study was to investigate the antifibrotic effect and anticoagulant ability of salvianolic acid B (SAB) inhalation solution on bleomycin (BLM)-induced idiopathic pulmonary fibrosis (IPF) in rats. We investigated how the osmotic pressure and concentration of SAB in an aerosol exerted effects. We also determined the aerodynamic particle size distribution and the uniformity of the delivery dose; these parameters were found to be suitable for inhalation. Compared with BLM group, the levels of hydroxyproline (HYP), collagen-1 (Col-1), tissue factor (TF) / coagulation factor VII (TF-VIIa), activated coagulation factor X (FXa), thrombin-antithrombin complex (TAT), fibrinogen degradation product (FDP) and plasminogen activator inhibitor-1 (PAI-1) decreased in SAB group. The increased expression of coagulation factor Ⅱ (FⅡ), coagulation factor X (FX), tissue type plasminogen activator (t-PA) and urokinase type plasminogen activator (u-PA) proved that SAB has obvious antifibrotic and anticoagulant effects. Western blotting and immunofluorescence further showed that compared with the BLM group, the SAB group of rats exhibited significant reductions in the expression levels of protease-activated receptors-1 (PAR-1) and phospho-protein kinase C (p-PKC) and increased expression levels of protein kinase C (PKC) in lung tissue. Furthermore, SAB reduced the infiltration of lymphocytes and neutrophils, protected the basic structure of the lung from destruction, inhibited the proliferation of fibrous tissue. Collectively, our data revealed that SAB may exert its antifibrotic and anticoagulant effects by preventing the expression of PAR-1 and phosphorylation of PKC.