Leukocytes are recruited during the early phase of venous thrombosis to the intact endothelial surface. (A) Leukocyte accumulation in DVT induced by 48 h of flow restriction. vG (top left) and immunohistochemical stainings (middle and right, top and bottom) for Ly6G⁺ MPO⁺ neutrophils and F4/80⁺ monocytes. Nuclei are counterstained with DAPI. Bars, 50 µm. The bottom left shows the quantification of neutrophils and monocytes. Results are mean ± SEM (n = 3). (B) Scanning electron microscopic images taken directly after partial IVC ligation showing the intact endothelium. After 6 h, a carpet composed of cell aggregates and fibrin can be visualized on the endothelial surface. Bars, 5 µm. (C) TEM images of venous vessels showing the anticoagulant endothelial cell lining (pseudocolored in yellow). Bar, 5 µm. Detail is shown in the right image. (D) Histological analyses of the IVC 6 h after flow reduction examining leukocyte recruitment in the early phase of venous thrombus formation. Histological sections in three different stainings (HE, vG, and MSB). Bars: (top row) 20 µm; (bottom row) 10 µm. Data are representative of n = 3 experiments per group.