Expression Of Vascular Endothelial Growth Factor And Matrixmetalloproteinases-9 In Intracranial Aneurysms

Objective To observe the pathological changes of the intracranial aneurysm walls and detect the expression of vascular endothelial growth factor (VEGF) and matrixmetalloproteinase 9(MMP-9) in intracranial aneurysm walls. To investigate the potential pathogenesis of the intracranial aneurysm.Methods 21 intracranial aneurysm specimens were resected after microsurgical clipping of aneurysm neck. Meanwhile, collect 13 normal pallium artery specimens from traumatic brain injury patients by decompression operation as control. Observe the pathological changes by hemotoxylin and eosin (HE) staining technique under light microscope,and observe the ultrastructural changes in the specimens by transmission electron microscope; Detect the expression of VEGF and MMP-9 in samples by immunohistochemistry technique, and record the positive site and intensity under light microscopy. Calculate the positive index(PI)。The relationship between the expression of VEGF and MMP-9 in aneurysm walls and clinical features: such as patient's age, Hunt&Hess grade, aneurysm size, rupture or not, and cerebral vasospasm was analyzed by statistical software.Results The vessel wall in the control group shows intact configuration;Meanwhile some acquired regressive characteristic changes such as endothelial cell damage,elastic fiber fracture,SMC absent,atherosclerosis,infiltration of inflammatory cells, bleeding etc. were detected in the intracranial aneurysm walls. In 13 normal pallium artery specimens shows negative expression of VEGF and MMP-9,while in aneurysm walls shows positive rate of expression of VEGF at 90.5%(19/21) and expression of MMP-9 at 85.7%(18/21);the expression of VEGF and MMP-9 mainly exist in the media and adventitia layers of the aneurysm walls, few in the endomembrane layers;There was no correlation between the expression of VEGF and MMP-9 and patients' age, hunt&Hess grade and cerebral vasospasm(P>0.05).The study indicated that the expression of VEGF and MMP-9 in large aneurysms are more common than in the small aneurysms; the ruptured aneurysms are more common than the unruptured aneurysms in expression of the MMP-9(P < 0.05).Conclusion 1. The pathological changes in aneurysm walls such as endothelial cell damage, elastic fiber fracture, SMC absent, atherosclerosis, infiltration of inflammatory cells, bleeding etc. indicated that acquired regressive characteristics may contribute in the pathogenesis of the intracranial aneurysm. 2.The higher expression of VEGF and MMP-9 in intracranial aneurysm walls comparing with the negative expression in control group indicated that VEGF and MMP-9 may also play an important role in pathogenesis of aneurysm.3.The higher expression of VEGF and MMP-9 in large aneurysms indicated it may play an important role in the development of intracranial aneurysms .4.The expression of MMP-9 in the ruptured aneurysms superior to the unruptured aneurysms showed it may related to the aneurysm's rupture.