Hydrogen peroxide inhibits proliferation and endothelial differentiation of bone marrow stem cells partially via reactive oxygen species generation.

AIMS: The present study was to investigate the effect of hydrogen peroxide (H2O2) on bone marrow stem cells and their endothelial differentiation and the underlying mechanisms in vitro.

MAIN METHODS: Rat bone marrow multipotent adult progenitor cells (MAPCs) were used as the source of bone marrow stem cells, and treated with H2O2 (with the final concentration from 0 to 50 μM) with or without N-acetylcysteine (NAC, 0.1 mM). Reactive oxygen species (ROS) was measured by electron paramagnetic resonance (EPR) and fluorescent microscope. Flow cytometry and immunoblotting were used to determine apoptosis and differentiation of MAPCs.

KEY FINDINGS: H2O2 generated a significant amount of intracellular and extracellular ROS in the culture system, substantially inhibited the proliferation of MAPCs and Oct-4 expression, and induced their apoptosis in a dose-dependent manner. Exposure to H2O2 also significantly attenuated the endothelial differentiation of MAPCs with reduced expression of endothelial markers CD31 and FLK-1 as well as impaired in vitro vascular structure formation. Both intracellular and extracellular ROS production from H2O2 were blocked by NAC. NAC treatment effectively prevented H2O2-induced reduction of Oct-4 expression in the cells. However, NAC treatment only partially prevented H2O2-induced apoptosis, and inhibition of cell proliferation and endothelial differentiation of MAPCs.

SIGNIFICANCE: H2O2 exposure suppressed Oct-4 expression in MAPCs through ROS-dependent mechanism, while increasing the apoptosis of MAPCs and inhibiting their proliferation and endothelial differentiation with a mechanism partially due to ROS generation in vitro.