Manipulated CD34⁺ cells influence development of IH. (A) 3-color immunohistologic analysis of carotid artery sections from injured WT mice taken on day 5 after injury. On day of injury, mice received 7.5 × 10⁵ CD34⁺ cells from ROSA-EYFP mice—these were exposed to thrombin 50 nM for 1 hour immediately before injection. Sections were stained with anti–α-SMA (red) and DAPI (blue). Original images taken at ×100 magnification. (B) Neointimal area (left panel) and intima-media ratios (right panel) of vessels taken from WT animals 28 days after injury. All received 7.5 × 10⁵ CD34⁺ cells on the day of injury from WT or Tg mice. The cells from WT mice were incubated in vitro for 1 hour, as indicated, prior to injection. Data derived from examination of 3 random sections from 5 different vessels. Data are presented as means plus or minus SEM.