Hemodynamics Plays More Important Role than Hyperlipidemia During the Dev elopment of Atherosclerosis,Artery Interposed to Vein don't develope athe rosclerosis in Cholesterol-fed Rabbits Hongqi ZHANG 1, Aijun SUN2, Jianguo JIA2, Danling Xu2, Keqiang WANG2, Junbo GE2, 1Department of Anatomy, Shanghai Medical College,fudan University, Shanghai(200032), China 2 Zhongshan Hospital, Fudan University, Shanghai, (200032) China To study autologous arterial grtafts interposed to veins, and to assess whether they would be susceptible to the development of accelerated atherosclerosis in hyperlipidemic rabbit model. Left common carotid artery (5 cm long) were interposed in the right external jugular vein pos ition of 30 adult male New Zealand White rabbits. After surgery, rabbits were fed with high c holesterol diet for 1, 2, 4, 8 and 12 weeks. Serum lipid (TC,TG,HDL-C.LDL-C) levels of all an imal were measured and the related blood vessel segments were harvested at different time po ints and observed under the light, transmission and scanning electron microscope. Vessel wall thickness,the content of collagen and elastin of tunica media was measured and analyzed by im age processing system. The apoptosis of vascular wall cells was also analyzed by TUNEL. Hyper lipidemia occurred in operated rabbits. Fatty streak and atherosclerotic plaques were observe d and lipid drops enriched in medial smooth muscle cells in control carotid arteries 1 month after surgery. In the grafted arteries, no fatty streak and atherosclerotic plaque were seen and the vessel wall thickness decreased continuously after surgery 3 months after surgery, grafted arteries possess similar structure s as that of veins. Smooth muscle cell apoptosis of grafted artery occured from inner layer to the outer one as time went by. The content of both collagen and elastin in the grafted artery decreased with the thim goes on,but collagen degrade apparently than elastin.Grafted artery interposed to vein did not develop atherosclerosis in cholesterol-fed rabbits and only atroph ic changes appear. Hemodynamics is more critical than hyperlipidemia in the development of atherosclerosis. blood lipid level comparison mMol/dl) ( 0 5 10 15 20 25 30 35 40 45 con 1w 2w 4w 8w 12w TG HDL-C LDL-C TC Fig1:the transverse sections of control arteries in diff erent time (H.E100). Pre-preoperation,w-week,m-month.arrow-fatty st reak. Fig 2: the transverse sections of grafted arteries i n different time(H.E100) the wall thickness become t hin gradually Fig 4: the elastic element and collagen stains of the gr afted segment at the moment before operation and at 1w,2 w,1m,2m and 3 m postoperatively.×200 Fig 3: :the vascular cell apoptosis(brown particles ) of the grafted segment at 1,2w ,1,2,and 3 m postopera tively ( TUNEL method).