Background: In oxidative stress, reactive oxygen species (ROS) production contributes to cellular dysfunction and initiates the apoptotic cascade. Autophagy is considered the mechanism that decreases ROS concentration and oxidative damage. Propofol shows antioxidant properties, but the mechanisms underlying the effect of propofol preconditioning (PPC) on oxidative injury remain unclear. Therefore, we investigated whether PPC protects against cell damage from hydrogen peroxide (H2O2)-induced oxidative stress and influences cellular autophagy.
Method: COS-7 cells were randomly divided into the following groups: control, cells were incubated in normoxia (5% CO2, 21% O2, and 74% N2) for 24 h without propofol; H2O2, cells were exposed to H2O2 (400 µM) for 2 h; PPC + H2O2, cells pretreated with propofol were exposed to H2O2; and 3-methyladenine (3-MA) + PPC + H2O2, cells pretreated with 3-MA (1 mM) for 1 h and propofol were exposed to H2O2. Cell viability was determined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide thiazolyl blue (MTT) reduction. Apoptosis was determined using Hoechst 33342 staining and fluorescence microscopy. The relationship between PPC and autophagy was detected using western blot analysis.
Results: Cell viability decreased more significantly in the H2O2 group than in the control group, but it was improved by PPC (100 µM). Pretreatment with propofol effectively decreased H2O2-induced COS-7 cell apoptosis. However, pretreatment with 3-MA inhibited the protective effect of propofol during apoptosis. Western blot analysis showed that the level of autophagy-related proteins was higher in the PPC + H2O2 group than that in the H2O2 group.
Conclusion: PPC has a protective effect on H2O2-induced COS-7 cell apoptosis, which is mediated by autophagy activation.
Keywords: Autophagy; COS-7 Cells; Oxidative Stress; Propofol.