The Effect of Fluid Shear Stress on the Growth Behavior of Vascular Endothelial Cells in vitro

Abstract

Cultured monolayers of bovine aortic endothelial cells were subjected to fluid shear stress in a specially designed apparatus, in which the rotation of a disc plate in a dish forced the culture medium to flow concentrically. The effect of the shear load was evaluated from the number of regenerated cells, in a denuded area that had been created by mechanically removing some cells before rotating medium, and the changes in DNA synthesis. Cells were stained with propidium iodide after digestion in RNase and the relative DNA content per cell was determined by microspectrophotometry. The cell number observed in the denuded area after the exposure to a shear stress of 1.3–4.1 dynes/cm for 24–48 hours was about twice as great as that of the static control. The DNA content of cells subjected to shear stress was significantly greater than that of paired, unstressed control cells. The histogram of DNA content per cell showed that the stress loaded cultures contained a relatively high proportion of cells located in the mitotic phase of the cell cycle as compared with the controls. These results indicate that fluid shear stress can stimulate the regeneration of and DNA synthesis in vascular endothelial cells.