Pulmonary embolism (PE) is the most life-threatening complication of venous thromboembolism, but few effective treatments have been discovered to attenuate chronic PE currently. In this study, we investigated the protective effects of salvianolic acid B (SalB) and ginsenoside Rg1 (Rg1)
combination (SalB/Rg1) on chronic PE and explored the potential mechanisms. The PE model was induced by 45 μm polystyrene microspheres and 20 mg/kg of SalB/Rg1 was administered to PE rats intraperitoneally. A histopathological analysis of the lungs and heart was performed through hematoxylin
and eosin staining and immunohistochemical analysis. The pulmonary index and right ventricular cardiomyocyte cross-sectional area were evaluated. SalB/Rg1 markedly downregulated pulmonary index, attenuated pulmonary interstitial changes, suppressed neutrophil infiltration, prevented collagen
deposition, and inhibited MMP-9 activities in the lung. We also found that SalB/Rg1 improved right ventricular hypertrophy accompanied by reducing the cardiomyocyte cross-sectional area. These data suggest that SalB/Rg1 played a protective role against microsphere-induced PE and holds a high
potential for the treatment of PE in the future.