大鼠动静脉内瘘失功时血管内膜病理改变和血管剪切应力的相关研究

Study on the mechanism of stenosis caused by abnormal intimal hyperplasia and shear stress change in arteriovenous fistula failure

目的揭示自体动静脉内瘘失功血管内膜病理改变和血管剪切应力的变化规律。方法研究对象:选取C57BL/6小鼠,分假手术组(n=20)和手术组(n=20)。手术组应用显微外科技术建立小鼠颈动静脉内瘘模型,假手术组不建立动静脉内瘘。检测指标:①血流动力学:测定动脉压、心率、血流速度、剪切应力值;②组织病理学:HE染色观察静脉壁厚度;PAS染色观察血管壁蛋白粘多糖;Gomori银染色观察血管壁网状纤维组织;醛品红弹力纤维染色观察血管壁弹力纤维组织;CD31、CD34免疫染色观察血管壁血管内皮细胞变化。结果①血流动力学检查:与假手术组比,手术组颈动脉内径变细,血管剪切应力明显增加(t=-6.840,P<0,001)。②组织病理学检查:HE染色显示手术组静脉血管壁明显增厚,管腔狭窄;PAS染色显示手术组中性粘多糖含量明显增多;Gomori银染色显示手术组纤维增生明显;醛品红弹力纤维染色显示手术组弹力纤维增生明显,排列紊乱;CD31、CD34免疫染色显示手术组血管内皮细胞膜缺乏连续性,被纤维组织增生破坏。结论动静脉内瘘手术后血管剪切应力增加,血管内膜异常增生,伴纤维增生紊乱、炎性细胞浸润增殖,进而血管壁增厚、管腔狭窄,是导致维持性血液透析患者自体动静脉内瘘功能障碍的重要机制。

Objective To reveal the rules of vascular intima and shear force changes in the autologous arteriovenous fistula failure.Methods C57BL/6 mice were divided into sham operation group(n=20)and surgical group(n=20).The operation group were subjected to a microsurgery to establish an internal arteriovenous fistula between carotid artery and jugular vein,while the sham group did not have the fistula.The examination indicators after the surgery included①hemodynamics:arterial pressure,heart rate,blood flow velocity and shear stress value;②histopathology:thickness of the venous wall by HE staining,mucopolysaccharide in vascular wall by PAS staining,damage of reticular fibers in vascular wall by Gomori silver staining,damage of elastic fibers in vascular wall by aldehyde-fuchsin elastic fiber staining,and changes of vascular endothelial cells by CD31 and CD34 immunostaining.Results①Hemodynamics:Compared with the sham group,the inner diameter of the carotid artery shrank,and the vascular shear stress increased significantly(t=-6.840,P<0.001)in the operation group.②Histopathology:In the operation group,pathological findings included thickened wall and narrowed lumen of the vein by HE staining,increased neutral mucopolysaccharide by PAS staining,evident fibrosis by Gomori silver staining,proliferation and disarrangement of elastic fibers by aldehyde-fuchsin elastic fiber staining,and interrupted endothelial cell layer by proliferated fibrous tissues in CD31 and CD34 immunostaining.Conclusion After arteriovenous fistula surgery,the increased shear stress in the fistula,the intimal hyperplasia,the proliferation and disarrangement of fibrous tissues and the infiltration of inflammatory cells lead to the thickness of the vessel wall and the stenosis of the vessel lumen,which account for the failure of autologous arteriovenous fistula in maintenance hemodialysis patients.