study of effects of cyclic tensile loading on morphology of human umbilical vein endothelial cell line in culture medium

introduction: endothelial cells are subjected to mechanical forces caused by pulsatile flow and pressure leading to hemodynamic shear stress and circumferential stress on endothelial layer. the study aimed at a quantitative evaluation of endothelial cell morphology by application of cyclic loading. endothelial cells respond to applied loads with adaptation and remodeling. such mechanisms are major determinants of the function of cardiovascular system. material and methods: a cyclic loading test device for cellular engineering was designed and manufactured to operate in wide ranges of applied strains, load frequencies and amplitudes, and stretch to release ratio. human umbilical vein endothelial cells were cultured on a medical grade silicon membrane and the membrane was stretched inside an incubator with strain amplitudes of 10%-25% and test durations of 4-10 hours. quantitative cellular morphological changes by cyclic loading were analyzed using designed image processing software. results: the results indicated marked changes in orientation of cells, from a random orientation to 70-80 degree alignments after loading. endothelial cells elongated due to loading and the shape index (si) decreased significantly. conclusion: it was concluded that morphology of endothelial cells is altered by cyclic loading: load amplitude and number of load cycles. the results may have applications in pathology of endothelial cells due to hypertension and in vascular remodeling following the effects of different loads on endothelial cells.