Figure 1.

Effects of inhibition of angiopoietin-2 (Ang2) and/or tumor necrosis factor (TNF) on vascular remodeling during Mycoplasma pulmonis infection (7 days). A–E: Confocal microscopic images of blood vessels in tracheal whole mounts stained for platelet endothelial cell adhesion molecule 1 (PECAM-1; green) to compare the narrow capillaries (arrowheads) in a ladder-like pattern across a cartilage ring in a pathogen-free mouse (A) with the enlarged, remodeled vessels in the same location in an infected mouse treated with vehicle (B). The vascular enlargement is less when anti-Ang2 (C) or anti-TNF (D) antibody was given during the infection. A and E: Corresponding vessels in an infected mouse treated with the antibody combination are similar to those in the pathogen-free mouse. F: Tracheal vessels are twice as large in infected mice (21 ± 1 μm) as in pathogen-free mice (10 ± 0.2 μm), but are smaller after treatment with anti-Ang2 antibody (16 ± 1 μm) or anti-TNF antibody (13 ± 0.4 μm). However, vessel size in infected mice that received both antibodies (9 ± 0.4 μm) is the same as in pathogen-free controls. G and H: Images of vessels stained for P-selectin (red) and PECAM-1 (green) to compare the absence of P-selectin in a capillary over a cartilage ring of a pathogen-free mouse (G) with strong P-selectin staining in a remodeled vessel in the same location of an infected mouse (H). I: In contrast, P-selectin is absent in a corresponding vessel of an infected mouse treated with the antibody combination. J–L: Tracheal mRNA expression for P-selectin (J), E-selectin (K), and Icam1 (L), expressed as fold change from pathogen-free mice, is greatest in the infected vehicle group and least in the antibody combination group. Data are given as means ± SEM (F and J–L). N = 5 mice per group (F); N = 4 to 5 mice per group (J–L). ^∗P < 0.05 versus pathogen-free group; ^†P < 0.05 versus infected vehicle group treated with phosphate-buffered saline vehicle. Scale bars: 50 μm (E, applies to A–E); 20 μm (I, applies to G–I).