OBJECTIVETo investigate the effect of different concentrations of glucose on the permeability of human umbilical vein endothelial cell monolayer and the protective effect of protein kinase C (PKC) inhibitor Ro-31-8425 against high-glucose exposure.

METHODSCultured human umbilical vein endothelial cell line EA.hy926 cells were exposed to 5.5 mmol/L glucose (control) and high-concentration glucose (10, 15, 20, 25.5, and 30 mmol/L), and the endothelial monolayer permeability was assessed by measuring the flux of FITC-labeled dextran (FITC-DΧ) across the endothelial cells. The cultured EA.hy926 cells were treated with 5.5 mmol/L glucose +saline, high glucose (25.5 mmol/L) +saline, or high glucose (25.5 mmol/L) +Ro-31-8425(10 µmol/L), and the level of PKC phosphorylation and endothelial monolayer permeability were evaluated.

RESULTSHigh glucose dose-dependently increased the permeability of the endothelial cell monolayer (P<0.01), and glucose at 25.5 mmol/L significantly increased the phosphorylation level of PKCα and PKCβ II in the cells (P<0.01). Treatment with 10 µmol/L Ro-31-8425 obviously attenuated high-glucose-induced PKCα and PKCβ II phosphorylation (P<0.01) as well as the increase of the cell monolayer permeability (P<0.01).

CONCLUSIONSHigh glucose increases the hyperpermeability of human umbilical vein endothelial cell monolayer mediated by the phosphorylation of PKC, and the PKC inhibitor Ro-31-8425 can reverse such effects.