Nomura H, Ishikawa C, Komatsuda T, Ando J, Kamiya A
Research Institute of Applied Electricity, Hokkaido University, Sapporo, Japan.
Biorheology. 1988;25(3):461-70. doi: 10.3233/bir-1988-25307.
To study the effect of fluid shear stress on cultured endothelial cells, we have developed an apparatus for the stress creation, which consists of a stainless steel disk driven by an electric DC motor and a stage to place a culture dish and to adjust the distance between the disk and the dish. When the disk is rotated, a concentric fluid movement occurs in the culture medium in the dish and exerts the shear stress on the endothelial cells cultured on the bottom of the dish. A theoretical analyses concerning the induced concentric flow velocity predicted that when the angular velocity of the disk rotation (omega) is slow enough to maintain a Reynolds' number of the order of 10, the exerted wall shear stress tau w on the endothelial cell monolayer is given for a constant as tau w = mu r omega/d where mu is the viscosity of the medium, d the distance from the plate to the monolayer and r the radial distance from the center of the dish. When omega is varied in a sinusoidal mode tau w also becomes sinusoidal, thus allowing to apply a pulsatile stress. In vitro experiments carried out to examine the validity of the theoretical results, using a suspension of polystyrene as a tracer with the ordinary culture medium and 99% ethanol, revealed excellent agreement of the measured velocity profiles with the predicted ones. The results demonstrated that the present apparatus can create both the steady and pulsatile wall shear stress on the culture cell layer as expected, unless Reynolds' number greatly exceeds the level of 10.
为了研究流体剪切应力对培养的内皮细胞的影响，我们开发了一种用于产生应力的装置，该装置由一个由直流电机驱动的不锈钢圆盘和一个用于放置培养皿并调节圆盘与培养皿之间距离的平台组成。当圆盘旋转时，培养皿中的培养基中会产生同心流体运动，并对培养在培养皿底部的内皮细胞施加剪切应力。对诱导产生的心形流速进行的理论分析预测，当圆盘旋转的角速度（ω）足够慢以保持雷诺数为10左右时，作用在内皮细胞单层上的壁面剪切应力τw为常数，即τw = μrω/d，其中μ是培养基的粘度，d是平板到单层的距离，r是从培养皿中心的径向距离。当ω以正弦模式变化时，τw也变为正弦波，从而可以施加脉动应力。使用聚苯乙烯悬浮液作为示踪剂，与普通培养基和99%乙醇一起进行的体外实验，以检验理论结果的有效性，结果表明测量的速度分布与预测的速度分布非常吻合。结果表明，除非雷诺数大大超过1水平，否则本装置可以如预期那样在培养细胞层上产生稳定和脉动的壁面剪切应力。
