Molecular mechanisms of improved adhesion and growth of an endothelial cell line cultured on polystyrene implanted with fluorine ions

Abstract

Endothelial cells derived from the bovine pulmonary artery (line CPAE, CCL 209, American Tissue Culture Collection, Rockville, MD, USA) were cultured on pristine or fluorine ion-irradiated polystyrene (5×10 12 or 5×10 14 F ions/cm 2, 150 keV). At 24-h post-seeding interval, the number of cells which adhered to the ion-modified polystyrene was significantly higher than on the unmodified material (+20 and +58% in cultures with the polystyrene irradiated by lower and higher ion doses, respectively). On day 7, the populations cultured on the irradiated substrates grew to higher densities, exceeding the controls at the lower and higher ion doses by 69 and 180%, respectively. The cells on ion-implanted samples were also larger (+70–95% and +90–99% at the lower and higher ion doses, respectively) and contained more protein (+16% at both ion doses). As was shown by ELISA, the polystyrene irradiated by the higher ion dose enhanced the expression of a cytoskeletal protein, vimentin (+65%) and protein of focal adhesion plaques, talin (+15%). The content of integrin α 5 β 1 (VLA-5), receptor for fibronectin, was increased at both lower and higher ion doses (+22 and +57%). In contrast to this, the content of ICAM-1 and vinculin was similar in cells grown on both pristine and ion-irradiated growth substrates. Moreover, the expression of VCAM-1 and ELAM-1 was lower by 11–14% in both ion dose groups. The present study has shown that ion implantation of polymers improves the adhesion and growth of endothelial cells without elevating the expression of immunoglobulin and selectin types of adhesion molecules. This surface modification should promote colonization of an artificial vascular prosthesis by endothelial cells and make it less vulnerable by immune system cells of the recipient.