Protective Effect of Crocin on Endothelial Cells Integrity: Studied by Surface Plasmon Resonance

Endothelial cell integrity and cell junction disruption are involved in many biological processes such as vascular permeability, progression of ischemic injury and cancer metastasis. In this study, the protective effect of crocin in endothelial cells integrity induced by vascular endothelial growth factor (VEGF) was monitored by surface plasmon resonance (SPR), an optical-based method. In addition, the expression of vascular endothelial (VE)-cadherins, the basic endothelial adhesion molecule, which plays a crucial role in the integrity of endothelial cells and cellular junctions, was assessed using flow cytometry (FC). Also, actin filaments which have main roles in alignment and maintaining the integrity of intracellular integrity were investigated by the fluorescence staining method. For the SPR test, the human umbilical vein endothelial cells (HUVECs) were immobilized on cysteamine-coated gold chips, and the effect of VEGF injection on crocin-treated endothelial cells was studied. The increase of the angle shift (∆Ө) with cells deposition near 0.8° indicated that cells were successfully immobilized on the gold chip surface. A linear relation ( R 2 = 0.95) was obtained between the amount of VEGF absorbed on the cell surface and the change in the response unit (RU) values. Our SPR curve results along with FC and imaging data suggest that the crocin has a protective effect on cellular integrity. Graphical abstract