Fig. 1

Development of pulmonary hypertension after injection of MCT in rats. a Survival of rats injected with MCT, with 100 % mortality at 45 days after MCT injection. b Significant right ventricular hypertrophy (RVW/BW) at 4 weeks after MCT injection (Control n = 10; MCT-treated n = 10 each). c Impairment of Ejection Fraction (EF) in the right ventricle (RV) and left ventricle (LV) at 4 weeks after MCT injection (Control n = 4; MCT-treated n = 5 each). d Changes in End-Systolic and End-Diastolic Volume (ESV and EDV) in rats injected with MCT showed increased ESV and EDV until 2 weeks after MCT injection (Control n = 4; MCT-treated n = 5 each). e Histological image of lung tissue in control rats (upper row) and 4 weeks post-MCT (bottom row). In the bottom left cross-section with two pulmonary arteries parallel to bronchioles, thickened arteries with massive hypertrophy and disorganization of vascular smooth muscle cells can be seen – one with a concentric hypertrophic artery and very small lumen; on the bottom-right picture, horizontal and oblique section of hypertrophic pulmonary artery. f Ultrastructure of lung from rats at 4 weeks after MCT injection. Upper-left image: degenerated endothelial cell; upper-right: activated endothelial cell with large nucleus and fibrosis of pulmonary tissue; bottom-left: pathological, multi-layered endothelial cells on thickened basal lamina; bottom-right: neovascularization in lung tissue: two endothelial cells (EC) surrounded with pericyte on thickened basal lamina. Data are presented as mean ± SEM. *P < 0.05, **P < 0.01, ***P < 0.001