[Effects of high and low shear stress on vascular remodeling and endothelial vascular cell adhesion molecular-1 expression in mouse abdominal aorta].

Objective: To establish a mouse model of abdominal aorta stenosis and analyze the alterations in the arterial wall response to high and low shear stress.

Methods: Twenty mouse were randomized equally into 4 groups, including 3 test groups (1, 7 and 14 day groups) with surgically induced stenosis of the abdominal aorta, and a sham-operated group without stenosis. The hemodynamics and the internal diameter of the blood vessel were measured by color Doppler flow imaging. The wall shear stress was calculated by Poiseiulle hydrodynamics formula (τ(m)=η×4×V(m)/D). Pathological examination and immunohistochemistry were performed to observe the arterial morphological changes and the endothelial vascular cell adhesion molecule-1 (VCAM-1) expression. The intimal-media thickness of the aorta was measured and endothelial VCAM-1 expression analyzed quantitatively.

Results: Regions of low and high flow shear stress were created upstream from the stenosis and within the stenosis, respectively. Compared with the sham-operated group, the mice with aorta stenosis showed gradually increased vascular intimal-media thickness and VCAM-1 expression intensity in the upstream aorta, but not within the regions of the stenosis.

Conclusion: Vascular remodeling may occur shortly after exposure to low shear stress, which plays a significant role in initiation and progression of the pathological process of atherosclerosis mediated by VCAM-1, whereas high shear stress may exert an anti-atherosclerotic effect.