Background: Perioperative hyperglycemia is a common clinical metabolic disorder. Hyperglycemia could induce endothelial apoptosis and dysfunction. Propofol is a widely used IV anesthetic drug in clinical settings. In the present study, we examined whether and how propofol reduced high glucose-induced endothelial apoptosis and dysfunction in human umbilical vein endothelial cells (HUVECs).
Methods: HUVECs were cultured with different concentrations (5, 10, 15, and 25 mM) of glucose for different times (4, 8, 12, and 24 hours). To study the effect of propofol, cells were incubated with different concentrations (0.2, 1, 5, and 25 μM) of propofol for 2 hours. In parallel experiments, cells were incubated in 5 mM glucose as control. Nitric oxide (NO) production was measured with a nitrate reductase assay. Cell viability was determined with a Cell Counting Kit-8. Protein expression of active caspase 3, cytochrome c, endothelial NO synthase (eNOS), p-eNOS-Thr, p66, protein kinase C βII (PKCβII), and p-PKCβII-Ser was measured by Western blot analysis. Accumulation of superoxide anion (O2˙) was measured with the reduction of ferricytochrome c. Cell apoptosis was determined with terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling staining.
Results: Compared with control, high glucose decreased NO production (P < 0.0001) and reduced cells viability (P < 0.0001) in HUVECs. Compared with high glucose treatment, pretreatment of cells with propofol (5 μM, 2 hours) reduced high glucose-induced inhibitory p-eNOS-Thr phosphorylation (P < 0.0001), increasing NO production (P = 0.0007), decreased high glucose-induced p66 expression (P < 0.0001) and p66 mitochondrial translocation (P < 0.0001), O2˙ accumulation (P < 0.0001), mitochondrial cytochrome c release (P < 0.0001), active caspase 3 expression (P < 0.0001), and enhancing endothelial viability (P < 0.0001). Furthermore, propofol inhibited high glucose-induced PKCβII expression (P = 0.0002) and p-PKCβII-Ser phosphorylation (P < 0.0001). Moreover, the observed protective effect of propofol was quite similar to that of PKCβII inhibitor.
Conclusions: Propofol, by a mechanism of decreasing high glucose-induced PKCβII expression and p-PKCβII-Ser phosphorylation, inhibits high glucose-induced p66 mitochondrial translocation, therefore protecting HUVECs from high glucose-induced endothelial dysfunction and apoptosis.