Figure 4. p21^–/– mice develop acute arterial inflammation after vascular injury.

Accumulation of (A) macrophages, (B) neutrophils, and (C) T lymphocytes in the femoral artery (neointima, media, and adventitia) of p21^+/+ (yellow bars) and p21^–/– (blue bars) at 1 and 2 weeks after vascular injury (n = 8; *P < 0.05 and **P < 0.01 versus p21^+/+ at same time point). (D) Representative photomicrographs of cross-sections of p21^+/+ (left) and p21^–/– (right) arteries immunostained for macrophages, neutrophils, and T lymphocytes (brown). Arrows indicate the internal elastic lamina. Scale bars: 20 μm.