Figure 4.

Effects of STI571 on the degree of muscularization; medial wall thickness of pulmonary arteries sized 25–50 μm, 51–100 μm, and greater than 100 μm; and internal lumen area of pulmonary arteries sized 25–50 μm. (A) Proportion of non- (N), partially (P), or fully (M) muscularized pulmonary arteries, as percentage of total pulmonary artery cross section (sized 25–50 μm). A total of 60–80 intraacinar vessels was analyzed in each lung. (B–D) Medial wall thickness of pulmonary arteries sized 25–50 μm (B); 51–100 μm (C); and greater than 100 μm (D). (E) The internal lumen area of vessels between 25 and 50 μm. Results from rats exposed to MCT for 28 and 42 days and STI571-treated rats (treatment from day 28 to 42 with 50 mg/kg/d) are presented. (F) Proportion of non-, partially, or fully muscularized pulmonary arteries from chronically hypoxic mice treated with STI571 (sized 20–70 μm). STI571 was applied at a dose of 100 mg/kg/d by gavage from day 21 to 35. *P < 0.05 versus control; ^†P < 0.05 versus MCT at day 28 or hypoxia at day 21; ^‡P < 0.05 versus MCT at day 42 or hypoxia at day 35.