Mechanical stretching was applied to normal human pulmonary artery endothelial cells (HPAEC) and human lung adenocarcinoma epithelial cells (A549) using an Flexcell® FX-4000T™ Tension Plus™ System. The cells, cultured on a flexible silicoelastic membrane, were stretched by the FX-4000T and cell images were recorded using a Stage Flexer Jr., a microscope and a CCD camera. Strain was calculated from the cell images before and after stretching. The strain on HPAEC was nearly equal to that on the membrane at any location when the cells were both sparse and confluent. On the other hand, the strain on A549 was nearly equal at any location on the membrane under both sparse and confluent conditions, but less than the strain on the membrane. The lower strain on A549 might be attributable to differences in cell shape from HPAEC.
