Abstract:Objective:To observe the relation between the change of arterial wall shear stress and the expression of matrix metalloproteinase 2（MMP-2）, and analyze its role in aneurysm formation.
Methods :Forty-eight New Zealand rabbits were equally divided into experimental and control groups. During the operation of the experiment group, a homogenic patch was implanted to the abdominal aorta to form an aneurysm, while sham operation was done in the control group. The arterial wall was harvested 1d, 7d, 14d, and 28d after operation, respectively. The diameter of the aorta was measured before harvesting. The level change of MMP-2 was observed by immunohistochemistry.
Results:In experimental group, the diameter of the aneurysm and its inflow and outflow tracts were enlarged at the 7-day after operation (P<0.05). Large amount of inflammatory cells infiltrated the arterial wall, and with pathologic change of elastic fibers of the media. MMP-2 reached the peak value in 1d after operation (P<0.01), and remained at a high level of expression continually (P<0.01).
Conclusions:When shear stress changes, the diameter of arteries increases and the expression of MMP-2 in the vessel wall is up-regulated. The enlargement of the aneurysm has a relationship with the continuous high expression of MMP-2. MMP-2 may be involved in the relationship between arterial wall shear stress changes and the formation of the aneurysm.