Effects and Mechanism Analysis of Vascular Endothelial Growth Factor and Salvianolic Acid B on 125I-Low Density Lipoprotein Permeability of the Rabbit Aortary Endothelial Cells

Atherosclerosis is the common pathological basis of cardiovascular and cerebrovascular disease. This study aimed to investigate the effects of vascular endothelial growth factor (VEGF) and salvianolic acid B (SalB) on the permeability of the rabbit aortary endothelial cells (RAECs) and to figure out the possible underlying molecular mechanisms. The extravasation of I-125-low density lipoprotein (I-125-LDL) through the RAECs was significantly increased by VEGF and decreased by SalB. Meanwhile, the tight junction-associated proteins occludin and claudin-5 were found downregulated by VEGF and the caveolae structure proteins caveolin-1 and caveolin-2 upregulated, which were abolished by the infusion of SalB. In addition, a marked increase in levels of cGMP and protein kinase G-1 (PKG-1) as well as activation of nuclear factor-kappa B (NF-kappa B) p65 were found after VEGF infusion, which were attenuated by SalB. This study demonstrates that VEGF and SalB can alter the LDL permeability of the RAECs by a paracellular pathway (downregulation of occludin and claudin-5) and a transcellular pathway (upregulation of caveolin-1 and caveolin-2), in which the cGMP/PKG/NF-kappa B signal pathway is possibly involved. The experimental results provide a new method and basic knowledge of prevention and treatment for cardiovascular and cerebrovascular disease.