THE MORPHOLOGICAL RESPONSES OF CULTURED BOVINE AORTIC ENDOTHELIAL-CELLS TO FLUID-IMPOSED SHEAR-STRESS UNDER SPARSE AND COLONY CONDITIONS

The morphological responses of cultured bovine aortic endothelial cell s to fluid-imposed sheer stress under sparse and colony conditions wer e studied. Applied shear stress was controlled to 2 Pa and the exposur e time was set between 1 and 24 hours. Before and after flow exposure, the shape index and the angle of cell orientation to flow direction o f each cell were measured. In the experiment under sparse condition, t he shape index was 0.38+/-0.13 (mean+/-SD) and cells almost randomly d istributed under the no-Ao isr condition. This randomness continued fo llowing application of shear stress for 24 hours, and no morphological difference between cells under the no-flow condition and those after exposure to shear stress was observed. In the experiment under colony condition, cells ill the center portion of the colony were round and r andomly oriented under the no-flow condition. After exposure to sheer stress for 24 hours, cells in the center portion were elongated and al igned with the flow direction, although cells in the periphery were ra ndomly oriented. From these results, we concluded that the degree of c ell-to-cell contact affects the morphological response of endothelial cells to fluid-imposed shear stress.