Abstract: Objective: To study the inhibitory effect of Boschniakia rossica polysaccharides (BRPS) on oxidative stressinduced apoptosis in vascular endothelial cells in vitro. Methods: A cellular model was established by treating human umbilical vein endothelial cells with tert-butyl hydroperoxide (tBHP). Cell viability was tested by methylthiazolyldiphenyltetrazolium bromide (MTT) assay, and the levels of malondialdehyde (MDA), superoxide dismutase (SOD) and reduced glutathione (GSH) were measured spectrophotometrically. The reactive oxygen species (ROS) was observed using the fluorescent probe dichlorofluorescein diacetate (DCFH-DA), the mitochondrial membrane potential (ΔΨm) was evaluated by JC-1 staining, and the apoptotic changes were detected by Hoechst staining and TdT-mediated dUTP nick end labeling (TUNEL) assay. The protein expression of Bax, Bcl-2, cytochrome c (Cyt c), truncated Bid (tBid), caspase-3, caspase-8 and caspase-9 were determined by Western blotting. Results: Pretreatment with BRPS significantly increased cell viability, reduced ROS level, inhibited MDA formation, increased SOD activity and GSH level, elevated ΔΨm, and suppressed tBHP induced apoptosis in vascular endothelial cells. Western blotting results showed that BRPS reduced mitochondrial tBid, reduced cytoplasmic Cyt c and Bax/Bcl-2 ratio, and suppressed the activation of caspase-3, caspase-8 and caspase-9 in vascular endothelial cells. Conclusion: BRPS has an inhibitory effect on oxidative stress-induced apoptosis in vascular endothelial cells in vitro, likely through inhibiting mitochondrial apoptosis and death receptor pathways.

Key words: Boschniakia rossica, polysaccharides, vascular endothelial cells, tert-butyl hydroperoxide, apoptosis