External stent inhibits long-term atherosclerosis of autologous vein graft in hypercholesterolemic rabbits / 第二军医大学学报

ABSTRACT

Objective: To study the long-term inhibitory effect of external stent on atherosclerosis of autologous vein graft in hypercholesterolemic rabbit and the possible mechanism. Methods: Hypercholesterolemic model was established in 15 rabbits and their bilateral jugular veins were anastomosed with bilateral carotid arteries. One jugular vein graft was stented with a polytetrafluoroethylene tube (external stent group) and the other receiving no stenting served as control (unstent group). Ultrasound was used to evaluate the haemodynamics 12 weeks after operation. The grafts were harvested to examine the thickness and area of intima and media, the deposition of lipid in the vessel wall, and the distribution of VCAM-1 positive cells. Scanning electron microscope (SEM) was used to evaluate the regeneration of endothelium. Results: Ultrasound results showed that the stent group was laminar blood flow and the control group had vortex flow. The thickness and areas of intima and media were significantly lower in the stent group than in the control group (P<0.01); the foam cells and deposition of lipid in the vein wall were significantly less in the stent group (P<0.01). No atherosclerosis plaque was founded in the stenk group. VCAM-1 positive cells in the control group were significantly more than those in the stent group (P<0.01). SEM showed that the endothelia were orderly, closely, and evenly arranged in the stent group; while those in the control group were in disorder, with larger gaps and different sizes. Conclusion: External stent can improve hemodynamics of vein graft, accelerate endothelium remodeling and reduce the deposition of lipid; it can also inhibit vein graft smooth muscle hyperplasia, and reduce foam cells in vein graft, indicating that external stent can inhibit the atherosclerosis of vein grafts in a long run.