Synergistic protective effects of escin and lowdose glucocorticoids against vascular endothelial growth factorinduced bloodretinal barrier breakdown in retinal pigment epithelial and umbilical vein endothelial cells

Abstract

Previous studies have shown that escin possesses glucocorticoid (GC)like antiedematous and antiinflammatory effects. The present study was designed to investigate whether escin exhibits synergistic protective effects against bloodretinal barrier (BRB) breakdown when combined with GC in an in vitro monolayer BRB model, based on retinal pigment epithelial (RPE) cells and human umbilical vein endothelial cells (HUVECs). The results showed that low concentrations of escin and triamcinolone acetonide (TA) administered separately did not affect BRB transendothelial (epithelium) resistance (TEER). However, when administered together, escin and TA significantly inhibited reduced BRB TEER following treatment with vascular endothelial growth factor (VEGF). Furthermore, lowconcentrations of escin and TA administered together significantly increased the expression levels of occludin and ZO1. This demonstrates that escin and GC have synergistic protective effects against BRB breakdown, and the molecular mechanisms may be related to the upregulation of occludin and ZO1 expression. The combination of escin with GC indicates a potential beneficial strategy for the treatment of breakdown of the BRB.