血流剪切应力（FSS）是血流与血管内皮之间产生的摩擦力，在内皮功能调节中具有重要作用。生理性FSS可保护血管内皮，而异常FSS如FSS的过低或振荡却能致内皮损伤，促进动脉粥样硬化（As）的发生发展。异常FSS的产生与中医"气虚血瘀"密切相关，益气补血活血类中药复方可能通过调节改善异常FSS来延缓As病程。课题组前期研究表明当归补血汤可通过抑制内皮炎症反应、促进内皮祖细胞（EPCs）数量和功能来保护血管内皮。本课题在既往研究基础上，观察当归补血汤对异常FSS致As病变模型动物血管内皮形态、炎症相关因子表达、外周血EPCs功能的影响；研究FSS影响下当归补血汤对内皮细胞及EPCs的作用；探讨当归补血汤对异常FSS致内皮损伤的保护作用、分子机制及信号通路。本研究的开展对于丰富并发展中医"气血理论"、拓展益气补血活血中药防治As及其相关疾病的新思路具有重要的学术价值和实际意义。

Fluid shear stress（FSS）arises at the interplay between blood flow and endothelial layer where it plays a pivotal role in regulation of endothelium function. A physiologic FSS protects against atherogenesis,whereas a disturbed FSS， such as a low or oscillatory shear is endothelium-impaired and pro-atherogenic. Occurrence of a disturbed shear is closely associated with the theory of qi deficiency and blood obstruction in traditional Chinese medicine（TCM），and TCM's formula such as Danggui-Buxue-Tang (DBT) for supplementing qi and blood and promoting circulation could turn a disturbed FSS into a physiologic one，which eventually is atheroprotective. Our former rearch findings suggested the effects of DBT on the anti-inflammation of vascular endothelium ，the increased colony forming units of endothelial progenitor cells（EPCs）， the promoting effects of functional activities of EPCs .In this study,we will observe the effects of DBT on endothelial injury，the expression of inflammatory factors of injured endothelium，the functional activities of circulating EPCs in a rabbit model of atherosclerosis induced by a disturbed FSS.We will detect the influence of DBT on functional activities of EPCs and endothelial cells exposed to FSS in vitro, and find the possible molecular mechanism and signaling way. This study will contribute to the TCM's theory of qi and blood.It will be of great importance and practice to develop a fresh opinion on preventing and curing atheroslerosis by using the formula for supplementing qi and blood and promoting circulation.