Fig. 2.

Small pulmonary arteries become progressively remodeled in pulmonary arterial hypertension (PAH). A: representative images from hematoxylin and eosin-stained pulmonary arteries (PA) of control and PAH rats at different stages of the disease. B: quantitative analysis of the vascular wall thickness. Twenty random PA per animal were analyzed. Vascular thickness was significantly higher in PAH rats compared with controls in both categories of PA examined (<150 and ≥150 μm). The remodeling of the smaller vessels progressed throughout the study, whereas hypertrophy of larger vessels showed an early increase and then stayed preserved. Results are expressed as box whisker plots (boxes: 25–75% percentile of the data; whiskers: minimum to maximum; line represents the median value); n = 8 rats for control and week 1 groups, n = 7 for week 2 group, and n = 6 for week 5 group. *P < 0.05 vs. control group; #P < 0.05 vs. week 1 group. Statistical analysis was performed by Newman-Keuls multiple-comparisons test. Open bars correspond to 100 μm.