Expression of matrix metalloproteinases 2 and 9 and their inhibitor-tissue inhibitor of metalloproteinase-1 in hypertension-induced cerebral aneurysm in rats

Objective To elucidate the effect of matrix metalloproteinases 2 (MMP-2) and MMP-9 and their inhibitors-tissue inhibitor of metalloproteinase-1 (TiMP-1) on the cerebral aneurysm. Methods A rat model of cerebral aneurysm was established. The dynamic changes of MMP-2,MMP-9 and TIMP-1 expression were examined in the process of aneurysm formation. Results In experimental group,with the development of hypertension, the expression of MMP-2, MMP-9 and TIMP-1 was increased one week after operation,peaked at first month and lasted until the 4th month after operation. The expression of MMP-9 was increased remarkably, which was 10 times higher than that of control group,but the MMP-2 and TIMP-1 were only two times higher than that of control group. In the control group,weak staining of MMP-2,MMP-9 and TIMP-1 was observed in the cerebral artery,and the expression of MMP-2 was little higher than that of MMP-9 and TIMP-1 .Conclusion The overexpression of the MMPs in artery was the main reasons of the aneurysm formation. The MMP-9 played a more important role in aneurysm formation.