Abstract
Cells in living tissue align to form the most efficient configuration for functioning. Vascular cells of arterial walls are continuously subjected to the periodic stretch induced by a pulsatile flow, which might affect the cellular orientation. In this study, endothelial cells (ECs), smooth muscle cells (SMCs) and fibroblast cells (FCs) derived from bovine aorta were cultured on the elastic translucent films made of polyurethane, which were subsequently stretched with variable amplitudes ranging from 5% to 20% and frequencies from 15 to 120 RPM for up to 24 hours. The time-lapse video-recorded views of phase contrast microscope were analyzed by a computerized image processor in order to quantitatively evaluate the cellular orientational response and morphological changes. The cells on the stress-loaded films aligned perpendicularly to the direction of stretch, while those on the stationary ones remained in random orientation. The orientation response proceeded with time, and was more pronounced with higher amplitudes or frequencies of the stresses. The response of SMCs and FCs advanced significantly more rapidly than that of ECs. Little morphological changes were observed, irrespective of stress-loading or nonloading. These mechanically induced orientation response of vascular cells might provide us a fundamental basis on the regulation of cellular orientation in vitro.
