Effect of glucose level on protein kinase C,permeability and adhesion of endothelial cells

Objective To study the effect of various glucose level on protein kinase C (PKC), permeability and adhesion of vascular endothelial cells. Methods The activity of PKC was determined by the incorporation of [γ 32 P] adenosine triphosphate (ATP) into exogenous substrate.The adhesion of vascular endothelial cells was measured by incubating human umbilical vein endothelial cells(HUVECs)with unactivated platelets labeled with 51 Cr.For the detection of endothelial permeability,albumin diffusion across HUVECs monolayers was measured. Results 20 mmol/L high concentration glucose (HCGS) could result in the largest activating level of PKC in HUVECs. Membranous PKC activity [(2.874±0.046) mmol·mg -1 ·min -1 ] was much higher than cytosol PKC activity [(1.215±0.019) mmol·mg -1 ·min -1 , P 0.01]. The largest rate of adhesion in HUVECs treated by 20 mmol/L high glucose level was (62.84±3.24)%, and the largest permeability rate of albumin across HUVECs was (0.32±0.002) ng/ml, which were all significantly higher than those of the control group ( P 0.01). The related coefficient between the total PKC activity and HUVECs adhesion rate was r =0.846, and the related coefficient between the total PKC activity and HUVECs permeability rate was r =0.734(all P 0.05). The PKC inhibitor, Calphostin C could inhibit PKC activation induced by HCGS and also markedly reduced the adhesion rate and permeability of HUVECs. Conclusion HCGS level may activate PKC, and increase the adhesion and permeability of vascular endothelial cells; while PKC inhibitor can markedly suppress the above effects.