The Change of Local Wall Shear Stress Accelerates Intima Hyperplasia and Atherosclerosis

The aim of this study was to create a novel animal model for local change of hemodynamics and analyze the arterial wall response to plaque-prone hemodynamic environments. A stenosis is modeled by a ring placed around the wall of the left common carotid artery. Numerical simulation of blood flow in the stenotic artery was performed to obtain the distribution of flow field and wall shear stress. Rabbits were fed with normal diet and sacrificed at 4 weeks after the operation. Plasma total cholesterol (TQ) high-density lipoprotein cholesterol (HDL-C), and triglycerides (TG) were determined by commercially enzymatic methods. The pathological slides were prepared and stained for optical microscopic observation. Results showed that in the immediate proximal and distal vicinity of stenosis, blood flow was disturbed significantly. The shear stress at the proximal part of ringer was obviously increased (>6Pa), while it was reduced (0~0.3Pa) at the axifugal part. At the end of 4 weeks, plasma total cholesterol, HDL cholesterol and triglyceride increased in high fat/high cholesterol rabbits. Two groups of rabbits had obviously plaque both at the proximal part and backend of ringer, but the proximal parties was more severity than the backend. Lipid deposited at neointima, elasticity fiber was derangement, and partly intima broken. Common carotid arteries by ringer can induce neointima hyperplasia successfully. Hemodynamics was changed by ringer attributed to the hyperplasia, while the gradient of shear stress plays the critic role.