EFFECT OF FLOW ON THE PROCESS OF ENDOTHELIAL-CELL DIVISION

In this study we investigated the effect of flow and the associated shear stress on the process of endothelial cell division. A shear stress of 7 N/m2 (70 dyne/cm2) was applied to a monolayer of bovine aortic endothelial cells (BAECs) by using a parallel-plate flow-chamber system. Dividing cells under flow conditions were qualitatively compared with those under static-culture conditions. In addition, the duration of some phases of the cell cycle (ie, mitosis and cytokinesis) was measured for both static and flow conditions. Dividing BAECs in static cultures bowed upward; however, when cells were preconditioned by at least 6 hours of exposure to flow, they stayed relatively attached to the substrate during the entire process of cell division. Cell area significantly decreased during division for both static-culture and flow conditions. Finally, although significant changes in the duration of phases were observed in single experiments during which cells were exposed to shear stress, any differences disappeared when the data for a large number of cells were combined. Hence, on average, flow and its associated shear stress did not affect the duration of the different phases of endothelial cell division.