Nonuniform strain of substrate induces local development of stress fibers in endothelial cells under uniaxial cyclic stretching

We have developed a novel uniaxial cyclic stretching technique to apply a ventral nonuniform strain to cells. In this system cells are grown on a glass-embedded silicone substrate instead of the commonly used uniform substrates. This unique substrate has been developed to give a strain gradient of 0.2%/μm across each individual cell. Bovine aortic endothelial cells (BAECs) were cyclically stretched up to a maximum strain of 50% at 0.5 Hz for 30 min or 3 hours, focusing on the effect of the ventral strain gradient on local cell remodeling. After the experiments, BAECs were fixed and stained with rhodamine-phalloidin to observe actin filament structure. BAECs showed local development of stress fibers and localization of cell nuclei at regions exposed to higher strain. This result suggests that BAECs may sense ventral nonuniform strain and remodel cytoskeletal structure accordingly followed by the movement of cell nuclei.