流体剪应力作用对内皮细胞变形的影响  

EFFECTS OF FLUID SHEAR STRESSES ON THE DEFORMATION OF ENDOTHELIAL CELL

作　　者：刘肖珩[1] P.WACHE X.WANG 陈槐卿[1] 

机构地区：[1]四川大学华西医学中心生物医学工程研究室,成都610041 [2]LEMTA-UMR-CNRS7563 Vandoeuvre-les-Nancy,France

出　　处：《生物物理学报》2003年第3期333-338,共6页Acta Biophysica Sinica

基　　金：国家自然科学基金项目(10102012)

摘　　要：血液流动和内皮的耦合是重要的生物医学问题,引起了学者们的广泛兴趣。目前已知流场剪应力对内皮细胞的形态和功能有重要影响,流体剪应力被认为是引起内皮细胞重建的始发信号。所以,了解流体剪应力与内皮细胞之间的相互作用机制是十分重要的。建立了一个理论模型来模拟流场剪应力与内皮细胞之间的相互作用。根据二维计算流体动力学方法研究了流体剪应力作用下内皮细胞表面的应力、压力分布。模拟结果表明:(1) 内皮细胞的变形随琢(对应于流体作用于细胞表面的剪应力)的变化而变化。当琢很小时(<0.02),流场剪应力对细胞变形的影响很小;随着琢的增大,细胞的变形也相应增大;当琢达到0.20以上时,细胞的变形变化很小,即细胞的形态保持相对稳定。(2) 流动引起了细胞表面应力和压力分布的不均匀,从而导致了细胞的变形,但内皮细胞的最大应力总是位于细胞的顶点。同时,用流室系统提供剪切流动,测量了不同剪应力作用下培养的人主动脉内皮细胞的变形,所得到的实验结果与数值模拟结果吻合。结果提示,由于剪切流动引起细胞表面应力分布的不均一,可能在细胞激活和细胞功能的调节(如细胞骨架的调节、粘附分子的表达与分布等)机制上具有特殊的作用。为应用流体动力学理论研究细胞(内皮细胞、白细胞等)The coupling of the endothelium and blood flow is an important biomedical problem and has drawn extensive research. It is known today that the shape and function of endothelial cell are influ-enced by the fluid shear stresses. Fluid shear stress being regarded as a primary triggering signal for cellular remodeling, it is important to understand the interaction mechanism between applied shear stresses and endothelial cell. In the present study, a theoretical model to simulate the coupling between the fluid shear stresses and the deformation of an endothelial cell was established. A two dimensional computation-al fluid dynamics (CFD) was used to determine the local distributions of mechanical stresses and pressure on the cell surface. The results showed that: (1) The deformation of an endothelial cell changed with α (corresponding to the shear stress imposed on cell surface by flow fluid). The deformation index stands on a smaller level when α (<0.02) was very small. Then, the deformation index increased with α increased until it kept relatively stable when α was greater than 0.20. (2) The distributions of mechanical stresses and pressure on the cell surface were not uniform, but the maximum shear stress was always at the top point of the cell. Meanwhile, the deformation of cultured human aortic endothelial cells (HAECs) exposed to shear flow was measured by using a flow chamber. It was found that the numerical results were well consistent with those of experiment. These results suggested that the non-uniformity of the mechanical stress distributions on cell surface might play a particular role in the mechanism of cell activation and in the regulation of endothelial cell functions (modification of cytoskeleton, distributions of

关 键 词：剪应力 内皮细胞 变形 流体动力学 血液流动 

分 类 号：Q27[生物学—细胞生物学] Q461