THE EFFECT OF LDL CONCENTRATION POLARIZATION ON ATHEROSCLEROSIS H Liu, G Wang, D Lei, L Ye Bioengineering College, Chongqing University, Chongqing Concentration polarization of low density lipoprotein (LDL) occurs in the arterial system and plays an important role in localization of atherosclerosis. We had previously confirmed LDL concentration heightened locally at those regions where wall shear stress (WSS) was low and the wall concentration of LDL was highest at the distal end of 40% stenosis round tube through numerical simulation. In this study we investigated the effect of LDL concentration polarization on atherosclerosis (AS) in vivo through a controllable LDL concentration polarization animal model. 24 New Zealand White rabbits received surgical intervention, the left common carotid arteries(LCCA) was operated a gel-silica pipe loop ligature operation with 40% stenosis degree, and the right common carotid artery (RCCA) as a sham operation control. All the animals were divided into four groups according to the different feeds, the normal diet and the high dietary lipid levels contained three different densities of cholesterol concentration (0.5%, 1%, 1.5%). Animals were sacrificed after 8 week. Then hemodynamic parameters of the common carotid artery were detected by Color Doppler Flow Imaging and WSS was calculated, and the pathological sections were prepared and stained for optical microscopic observation. The results showed WSS of LCCA is lowest in the group of 1% cholesterol concentration, and there were AS pathological changes with different extent at the distal end of LCCA of all groups, especially it was most evident in 1% cholesterol group, but no pathological changes in RCCA. This results supports that atherogenesis is more obvious in the regions where LDL concentration polarization is significant and WSS is low. Funding: Supported by grants from CMOE (104158, B06023, CQUCX-G-2007-3) and CMC(03001).