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. 2022 Jul 7;60(1):2100327. doi: 10.1183/13993003.00327-2021

FIGURE 3.

FIGURE 3

Id 1/3 knockout mice (Ids cDKO) mice are susceptible to pulmonary arterial hypertension (PAH) and pulmonary vascular remodelling. a–e) Assessment of a) right ventricular systolic pressure (RVSP) and total pulmonary vascular resistance index (tPVRI) (tPVRI=RVSP/cardiac index); b) Fulton index (right ventricular hypertrophy, RV/(LV+S)); c) tricuspid annular plane systolic excursion (TAPSE); d) cardiac output (CO) and cardiac index (CI) (cardiac output/body weight); and e) left ventricular ejection fraction (LVEF) and left ventricular fraction shortening (LVFS) in control mice (control) and Id cDKO mice without spontaneous arterial hypertension (non-SPAH) or with SPAH at age 6 months. Mice were defined as having SPAH when their RVSP was >25 mmHg. The numbers of mice that did or did not develop SPAH among the total mice in each group are shown on the x-axis. f) Representative immunofluorescence staining of α-actin smooth muscle (α-SMA, green) and the endothelial cell marker CD31 (red) in lung sections revealed thickened arterial walls in Id cDKO mice with SPAH at 6 months of age. Nuclei were counterstained with 4′,6-diamidino-2-phenylindole (blue). Scale bars=15 μm. g) Representative images of vascular remodelling in the distal arterioles stained with elastin and immunostained (IHC) α-SMA, and representative images of pulmonary arteries stained with haematoxylin and eosin (H&E). The lung sections were obtained from control and Id cDKO mice with non-SPAH or SPAH at 6 months of age. Scale bars–25 µm. h) Vessel muscularisation analysis based on α-SMA labelling on the lung sections from control and Id cDKO mice with SPAH at 6 months of age. i) Pulmonary vascular remodelling rate based on Elastica van Gieson (EVG) staining on the lung sections from control and Id cDKO mice with or without SPAH at 6 months of age. The vessels 25–100 μm in diameter in f) and g) were quantified and n=6–12 mice for each group in h) and i). RV: right ventricle; LV: left ventricle; S: septum; ns: nonsignificant. All results are presented as mean±sem. *: p<0.05, **: p<0.01, ***: p<0.001 and ****: p<0.0001 versus control and other groups as determined using one-way ANOVA with post hoc tests (Dunnett's multiple comparisons test in panels a–e and h, and Tukey's multiple comparisons test in panel i.