TRAIL expression in pulmonary arterioles increases with pulmonary vascular remodeling in the MCT rat model. Representative photomicrographs of serial lung sections from saline- and MCT-treated rats 14, 21, and 28 d after injection. Sections were stained with Alcian Blue Elastic van Gieson (ABEVG) or immunostained for α-SMA, von Willebrand factor (vWF), or TRAIL. TRAIL-expressing cells are present within the media and perivascular regions of remodeled small pulmonary arteries. All images are representative of n = 7 rats per group at each time point. Bars, 50 µm.