Effect of Wall Shear Stress Gradient on Cells: Distribution of Deformation and Rotation
Hiroki Yonezawa, Shigehiro Hashimoto, Ryuya Ono
The effect of wall shear stress gradient on the deformation and rotation of each cell was investigated in vitro. To make a Couette-type of shear flow, the culture medium fluid was sandwiched with a constant gap between parallel walls: a lower stationary culture disk, and an upper rotating disk. Mouse fat precursor cells (3T3-L1) were used in this experiment. After cultivation without flow for 24 hours for adhesion of cells on the lower plate, a shear stress of less than 2 Pa was continuously applied to cells for 24 hours in the incubator. The behavior (deformation and major axis angle) of each single cell was tracked using time-lapse images observed by an inverted phase contrast microscope placed in the incubator. For wall shear stresses of less than 1.9 Pa, each cell exhibited active behavior: migration, deformation, and rotation. Whereas, the cells transformed into spheres when wall shear stress was higher than 1.9 Pa. In addition, the cells were observed to tilt against for a wall shear stress gradient approaching 50 Pa/m. Full Text
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