Background: Vascular endothelial cells play an important role in maintaining cardiovascular homeostasis. Oxidative stress is a critical pathogenic factor in endothelial cell damage and the development of cardiovascular diseases. In this study we evaluated the effects of propofol on oxidative stress-induced endothelial cell insults and the role of serine-threonine kinase Akt modulation of endothelial nitric oxide synthase (eNOS) as a mechanism of protection.
Methods: Human umbilical vein endothelial cells were used as the experimental model. Hydrogen peroxide (H2O2, 100 microM) was used as the stimulus of oxidative stress. Study groups included 1) control; 2) cells incubated with H2O2 alone; 3) cells incubated with propofol (50 microM) alone; or 4) cells pretreated with propofol 50 microM for 30 min then co-incubated with H2O2. Cell viability was assessed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and Trypan blue dye exclusion test. Cell apoptosis was evaluated by Hoechst 33258 staining. Caspase-3 activity was determined by the colorimetric CaspACE Assay System. Expressions of Akt, phospho-Akt, and eNOS were detected by Western blotting.
Results: H2O2 decreased cell viability, induced apoptosis, and increased caspase-3 activity in human umbilical vein endothelial cells. Propofol significantly protected cells from H2O2-induced cell damage, apoptosis and decreased H2O2-induced increase in caspase-3 activity. Propofol treatment significantly increased eNOS expression compared to control and H2O2-stimulated cells. There was no significant difference in phospho-Akt (Ser 473 or Thr 308) expression among the groups.
Conclusions: Propofol 50 microM can reduce H2O2-induced damage and apoptosis in endothelial cells, by suppressing caspase-3 activity and by increasing eNOS expression via an Akt-independent mechanism.