The Experimental Study Of MMP-9、TIMP-1 Expression And Significance During Carotid Atherosclerosis In Rabbits

Since the new century,due to the improvement of people’s living standards,lifestyle changes,carotid artery stenosis has gradually become one of the main causes of life and safety threats;carotid artery stenosis is mainly due to carotid atherosclerosis(Carotid atherosclerosis,CAS)caused by the formation of carotid luminal stenosis,the incidence of high probability of people over the age of 60 suffering from carotid atherosclerotic stenosis up to 9%,its good occurred in the beginning of the internal carotid artery And the bifurcation of the common carotid artery.Carotid stenosis and occlusion can lead to cerebral ischemia,resulting in ischemic stroke,serious may lead to death.In recent years,people have a clear understanding of the pathophysiology of CAS,CAS is considered to be active inflammatory process,not simply lipid infiltration.In the course of CAS,matrix metalloproteinases(MMPs)and imbalances in Tissue Inhibitor of Metalloproteinases(TIMPs)can lead to excessive degradation of the extracellular matrix and basement membrane of the vascular endothelial cells,which is the main cause of CAS formation one.Activated collagenase(MMP-9)can degrade extracellular matrix(ECM),break the ECM synthesis and degradation of the balance,so that excessive deposition of collagen,thereby affecting vascular remodeling.The study of MMPs on atherosclerosis(AS)has gradually become a hotspot in recent years.This study mainly explored the expression of MMP-9 and TIMP-1 in the process of CAS formation and its significance,and aims to provide a theoretical basis for the pathogenesis and early diagnosis of CAS.Objective :First copy the stability of the New Zealand rabbit model of CAS,observe its pathological change characteristic,developing and the artery wall plaque group matrix metalloproteinases(MMPS)-9 and metal protease inhibitors(TIMP)1expression level and CAS form relationship,establish the CAS form an important molecular mechanism,provide the carotid atherosclerotic stenosis disease intervention targets.Methods : Choose healthy New Zealand pure white rabbit,a total of 24,maleand female half,weight between 2.1 to 4.1 kg,gas drying damage method combined with continuous feeding high-fat food CAS form the animal model is set up;Experiment is divided into A,B,C,D four groups(6)in each group,for blank control group A(don’t do any processing,common feed),B to form A model combined with continuous feeding high-fat food after 2 weeks,C to form A model combined with continuous feeding high-fat food after 4 weeks,D form mode combined with continuous feeding high-fat food after 8 weeks.Ear margin venous air embolism executed after modeling,the original neck incision carotid artery dissection,carotid artery wall and plaque group,make biopsy specimens.HE staining to observe the carotid artery wall changes and plaque formation;Immunohistochemical staining method to detect the artery wall,MMP-9 in the plaques and the semi-quantitative expression of TIMP-1;Western blot method to detect the artery wall and plaques of MMP-9 and TIMP-1 protein in the relative expression level.Results : HE staining results suggest that A group of carotid artery intimal smooth,no obvious atherosclerotic plaque formation,local and group B with A small plaque formation and plaque contains A small amount of inflammatory cell infiltrates,and the group C and group D visible non-uniformity carotid intimal thickening,narrow lumen limitations,foam cell aggregates increased significantly,the endothelial cells is obvious swelling degeneration,membrane in smooth muscle cell hyperplasia is apparent,macrophage and lipid content significantly increased,more lipid fiber cap formation,prompt the CAS building success.Immunohistochemical staining results suggest that A set of tube wall are seen in small amounts of MMP-9and TIMP-1 staining positive;B group of artery wall and plaque tissue MMP-9 and TIMP-1 staining positive slightly increased;Group C and group D arterial wall and MMP-9 in plaque tissue staining positive significantly increased,while positive TIMP-1 significantly reduced,group D MMP-9 staining positive cells and intensity obviously higher than that of group C,and the intensity of staining positive cells and TIMP-1 is lower than that of group C.Tips in the process of the CAS form,carotid artery wall and plaques in the organization the expression of MMP-9 was gradually increased,while the expression of TIMP-1 presents downtrend to a certain extent.Western blot results suggest that A group of organizations with A small amountof MMP-9 and TIMP-1 protein expression,group B in MMP-9 and TIMP-1protein expression levels,and MMP-9 in group C and group D protein expression level increased significantly,group D was higher than group C,and TIMP-1 protein expression level is obviously decrease,contrast between group D is lower than in group C.Conclusion : Gas drying damage method combined with continuous feeding high-fat foods can build stable rabbit model of CAS formation,carotid artery wall and MMP-9 high expression in plaque group and low expression of TIMP-1 May be important formation mechanism,the CAS by intervening in the reduced expression of MMP-9 or promote the expression of TIMP-1 May be reversed CAS to form,is expected to become potential targets of CAS.