| BACKGROUND Atherosclerosis is a chronic systemic inflammatory disease of the arterial wall initiated by artery endothelial cell injury and dysfunction. With the risk factors keeping existence, the damage and repair concomitantly penetrated through the process of atherosclerotic disease. With the ability of differentiating into endothelial cell, Endothelial Progenitor Cells (EPC) participates in the repair of the endothelium after being injured and angiogenesis. Currently, many evidences suggest that circulating bone marrow-derived endothelial progenitor cells play a protection role in atherosclerosis. The interaction of Stromal cell- derived factor1 alpha (SDF-1α) and its receptor CXCR4 may promote the mobilization of bone marrow stem cells and homing to injured endothelium and strengthen the recruitment of inflammatory cell.OBJECTIVE To study the effect of CXCR4 antagonist AMD3100 on the atherosclerotic lesion, the expression of TNF-αand NF-κB and the activity of bone marrow Endothelial Progenitor Cells in apoE-/- mice, so as to approach the specific role and possible mechanisms of SDF-1α/CXCR4 on atherosclerosis.METHODS 36 male apoE-/- mice, 8 weeks old, randomly divided into three group:①normal food group②high fat group [PBS 0.1ml/2d, intraperitoneal injection (IP)];③AMD3100 group (high fat+AMD3100 2.5mg/kg/2d, IP). Animals from high fat group and AMD3100 group were fed with western food which concluding 15% fat and 0.25% cholesterol. After feeding 12 weeks, all mice were anesthetized by 0.2～0.3ml Urethane (20%) and removed eyeball in order to obtain blood preparation. Serum lever of SDF-1αwas measured by ELISA. Serum triglyceride (TG), total cholesterol (TC), and high density lipoprotein cholesterol (HDL-C) were determined by commercially enzymatic methods. The Hematoxylin/Eosin dyeing of paraffin section was used to detect the area of atherosclerotic plaque of apoE-/- mice aortic root transaction. The lipidoses of aortic sinus was detected by oil red O staining frozen section. The expression of CXCR4, TNF-αand NF-κB measured by immunohistochemistry. Gene and protein expression was analyzed by semi-quantitative RT-PCR and Western Blot, respectively. The bone marrow cell were isolated and cultured by way of different speed of adherence and Micropore-Method from the high fat group and AMD3100 group. CD133+ VEGFR-2+bone marrow cell were identified as endothelial progenitor cells by immunofluorescence. The proliferation, migration and adhesion of endothelial progenitor cells were detected by MTT assay, Transwell and Adhesion test, respectively. By counting the typical endothelial progenitor cells-colony forming units (EPC-CFUs) and observing the size and cell density of secondary EPC-CFUs, we measured the clonality of endothelial progenitor cells from the two groups'mice.RESULTS AMD3100 treatment resulted in a significant increase of atherosclerotic lesion area and the expression of TNF-αand NF-κB in apoE-/- mice. Serum TG, TC, HDL-C and LDL-C concentrations were not markedly changed. AMD3100 reduced SDF-1αserum lever and CXCR4 expression on artery wall. The proliferation, migration, adhesion and clonality of endothelial progenitor cells derived from AMD3100 group were attenuated in comparison to the high fat group. The expression of CXCR4 mRNA and protein of AMD3100 group were also lower to high fat group.CONCLUSIONS Atherosclerotic lesions in apoE-/- mice were aggravated by long term administration of CXCR4 antagonist AMD3100. Possible mechanisms of this action for AMD3100 are associated with the upregulation of proinflammatory factors TNF-αand NF-κB and the inhibition of the proliferation, migration, adhesion and clonality of bone marrow endothelial progenitor cells and the down-regulation of CXCR4 expression on endothelial progenitor cells.
|
PDF Full Text Request