The Relationship Between Changes Of CD40L Levels And Lesion Structures In Human Coronary Atherosclerotic Lesions

Objective: In this study,in order to investigate the role of CD40-CD40 L signal in the development of atherosclerotic lesions in human coronary arteries,we observed the changes of morphological characteristics in human coronary atherosclerotic plaque,and detected the expression of CD40 L and matrix metalloproteinase-9(MMP-9)in the lesions.Methods: 60 cases of human coronary artery with atherosclerosis(AS)were collected as experimental group,and divided into four groups according to the differently pathological stages: 5 cases of fatty streak,19 cases of fibrous plaques,18 cases of atheromatous plaque,18 cases of secondary change;and 12 cases without pathological changes as control.Histological structure were observed by conventional Hematoxylin Eosin(HE)staining and measured the relevant structure indicators of the lesion by image analysis software;the expression of CD40 L and MMP-9 at protein level were detected by Immunohistochemical PV two steps method;the expression of CD40 L and MMP-9 at mRNA level were detected by reverse transcription-quantitative real time PCR(RT-qPCR);analysis of the relationship between the expression of MMP-9,CD40 L and the changes of coronary atherosclerotic focal structure were analized by Statistics.Results: 1.The control group of coronary artery wall was thin,the structure of each layer including intima,media and adventitia were all uniform thickness and intima was smooth and integrity.The experimental group varied from fatty streak period to the secondary lesion period on gross and the lesions of vascular wall thickened and lumen stenosed in different degrees,of which some foci had calcification,hemorrhage and thrombosis.Under light microscope,we could observe foam cells hyperplasia,vascular wall thickness and lumen without obvious change in lighter degree;while we could observe obvious atheromatous necrotic foci,and even intraplaque hemorrhage or thrombosis,vascular wall thickening and lumen stenosis obviously in severelesions.2.The CD40 L protein had no expression in the coronary arteries of control group,while in the experimental group,the positive expression increased obviously,mainly expressed in the foam cells and inflammatory cells' cytoplasm at the shoulder,bottom,fiber cap area and aroud the necrotic lesions.According to the average optical density value,compared with the control group,the experimental group was significantly increased(P<0.05),and the different expression of CD40 L level was significant among the experimental groups(P<0.05).3.The control group showed a small amount expression of MMP-9 protein in medial smooth muscle cells and intimal foam cells' cytoplasm.While the experimental group showed much of cytoplasmic expression in foam cells and inflammatory cells of the atherosclerotic plaque,mainly at the shoulder,bottom,fiber cap area and aroud the necrotic lesions;besides,smooth muscle cells of media expressed a little.According to the average optical density value,the experimental group was significantly increased compared with the control group(P<0.05).In addition,the difference expression of MMP-9level presented significantly differences among the experimental groups(P<0.05).4.Using RT-qPCR to detect the mRNA of CD40 L and MMP-9 in the coronary vascular tissue,results showed that the experimental group of CD40 L at mRNA level was significantly increased compared with the control group(P<0.05),and only the secondary lesion period presented significantly differences(P<0.05).The expression of MMP-9 had no statistical significance between experimental group and control group or among the experimental groups(P>0.05).5.The protein levels of CD40 L and MMP-9 were positively correlated with each other,which also were positively correlated with the thickest thickness of the intima,the necrosis thickness and the degree of stenosis(P<0.05),and presented a negative correlation with fiber cap thickness percentages.Conclusion: 1.The expression of CD40 L at protein level significantly enhance in the atherosclerotic plaque of human coronary artery.2.The expression of MMP-9 at protein level is increased and its expression is positive correlation with CD40 L and correlate with the changes of vascular structure.3.We suggested that CD40 L might promote the expression of MMP-9,which could enhance the extracellular matrix(ECM)decomposition,ultimately leading to lesions structuredeveloping,including the fibrous cap thinning and the plaque breaking.