Expression And Significance Of MMP-2,MMP-9,TIMP-1 In Intracranial Aneurysms

Objective:To examine the expression of matrix metalloproteinases-2 (MMP-2),matrix metalloproteinases-9 (MMP-9) and Matrix metalloproteinase inhibitor-1 (TIMP-1) in intracranial aneurysms and compare them with those exp ressed in normal brain vessels tissue. To hope to obtain useful informations for better understanding of the pathogenesis of intracranial aneurysms.Methods:Thirty-one surgical specimens of human cerebal aneurysm in the First Affiliated Hospital of Nanchang University during Oct,2009 to July,2010 were choosen.All specimens were got from dissecting after clinpping the aneurysm in craniotomy.Including 13 of cases anterior communicating aneurysms,8 cases of middle cerebral artery aneurysms,6 cases of posterior communicating aneurysms,2 cases Aneurysm of vertebral artery,2 cases of anterior cerebral artery aneurysms.Sixteen control specimens including 7 cases of superficial temporal artery,4 cases of middle meningeal artery, and 5 cases of pial artery.These specimens came from hematoma removal and internal decompression.To observe the expression of MMP-2,MMP-9 and TIMP-1 in human cerebral aneurysm with immunohistochemical method.Results:1.Naked eyes observation:The aneurysms look like berry before clipping.Most specimens were dark brown,dark red and gray.There were thrombosis in some cavities of the aneurysms. Calcification could be seen in some of the aneurysms specimens.The wall of the aneurysms were various,the top were thinner than the basilar part.Most aneurysms were made of thin fibrous tissue.texture were various,some were soft.and some were stiff.2.HE staining:It is difficult to distinguish the tunica interna,the tunica media and the tunica externa.The three-layered structure of normal brain artery wall were lost. Internal elastic layer almost disappeared,and endothelial cell were reduced, thrombosis and part organization could be seen.The normal structure of tunica media layer were disapeared. smooth muscle atrophied and smooth muscle cell were reduced even disapeared.were filled with fibrous tissue,and the fibrous tissue arrange disord. Tunica externa layer were thin, mainly fibrous tissue, no external elastic layer. Inflammatory cell infiltrate could be seen in every layer of the aneurysms wall, mainly macrophages and lymphocytes.The aneurysmal wall showed atherosclerosis-like changes, lipidoses could be seen in the cell,mainly in the tunica interna and tunica media.3.The immunhistochemistry staining:The high expression of MMP-2, MMP -9 in human cerebal aneurysmal walls,were 87.10%(27/31) and 80.65% (25/31),MMP-2,MMP-9 expressed in tunica interna,tunica media and tunica externa.But no erpression of MMP-2,MMP-9 in control group, indicating the statistical significance.The positive rate of TIMP-1 in human cerebal aneurismal walls and control group were 87.10%(27/31) and 56.25%(9/16), indicating the statistical significance.Conclusions:1.The pathological changes of intracranial aneurysms mainly internal elastic layer almost disappeared,and endothelial cell were reduced and Tunica externa layer were thin. Inflammatory cell infiltrate could be seen in every layer of the aneurysms wall. Mainly macrophages and lymphocytes.2.The high expression of MMP-2,MMP-9 and TIMP-1 in human cerebal aneurismal walls,they express in every layer.3.MMP-2,MMP-9 and TIMP-1 were closely related with intracranial aneurysms, maybe MMPs and TIMP common to maintain the homeostasis of extracellular matrix metabolism occurrence imbalance were closely to related intracranial aneurysm. Specific mechanism needs further research.