Expression and location of intracellular tissue factor in atherosclerosis stable plaque of ApoE-/- mice

In the ApoE(-/-) mouse model of atherosclerosis (AS) stable plaque, the expression and location of intracellular tissue factor (TF) in the cellular components of AS stable plaque were investigated in order to explore the cellular mechanism of AS thrombosis. Pathological changes of the stable plaque were observed under a microscope. The expression of TF protein was examined in aortic stable plaque of mice by using immunohistochemistry. Color image planimetric system was used to analyze the histological components of the stable plaque and the TF distribution. Under the confocal microscope, the intracellular TF location in the stable plaque of mice was observed. The results showed the cellular area was the major part of stable plaque (67.36%+/- 6.52%, P < 0.01). The percentage of total area occupied by cellular area was significantly larger than atheromatous gruel and acellular area (P < 0.01). Macrophages and smooth muscle cells (SMC) were major cells in the cellular area. The percentage of total area occupied by SMC was significantly larger than by macrophages (P < 0.01). Multiple linear regression analysis showed there was a positive correlation between TF area and SMC area (r=0.616, P=0.008), and no correlation was found between TF area and macrophage area (r=0.437, P=0.08). Pictures of color image planimetric analysis of TF and SMC were merged to highlight areas with co-localization (yellow), it was concluded that the process could be a cell-mediated TF expression in the stable plaque. SMC may be the major source of TF in AS without plaque rupture.