Fig. 2

Pathological changes in the animal model of CTEPH. Note: No significant changes were apparent in the sham group (a). Macroscopic pathology demonstrated reddish-brown thrombi (black arrow) adhered to the left lower lobar artery wall in the 1-week and 2-week subgroups (b) and a dark red pulmonary infarction (white arrow) in the 4-week group (c) following repeated embolization. Histological sections of pulmonary artery demonstrated organized tissue (white arrow) on the surface of the thrombi (black arrow) and invasive growth into it (d, HE, 20×). The pulmonary artery endothelial cells (white arrow) were closely connected with the thrombus (e, HE, 40×) and the thickened endothelium was present in the distal pulmonary artery (f, HE, 40×)