Isolation of the Broccoli Polypeptide Component and Its Protective Effect on Vascular Endothelial Cell Injury Induced by Hydrogen Peroxide / 中国药学杂志

ABSTRACT

OBJECTIVE: To investigate the protective effects of broccoli polypeptide component on vascular endothelial cells injury induced by hydrogen peroxide (H2O2). METHODS: The broccoli polypeptide was isolated by methods of alcohol precipitation and sephadex G-25 gel filtration chromatography. The EVC-304 cells were cultured in logarithmic growth phase and incubated with 100 μmol·L-1 H2O2 for another 12 h after pretreatment with broccoli polypeptide component (1, 2, 4, 8 μg·mL-1) for 24 h. Cell viability was determined by MTT assay, the change of cell apoptosis and mitochondrial membrane potential were measured with cytoanalyzer, the activity of SOD and the level of MDA were detected with the kit and the expression levels of Cleaved Caspase-3, Cyto C, Bax and Bcl-2 were detected by Western blotting. RESULTS: Four main elution peaks were obtained after Sephadex G-25 gel filtration chromatography and the broccoli polypeptide components II was selected subsequent experiments. The experimental results demonstrate that compared with the normal control group, the survival rate of H2O2-treated cells was decreased and the apoptosis ratio was increased significantly (P<0.01), mitochondrial membrane potential depolarization ratio was increased significantly (P<0.01), mitochondrial membrane potential depolarization ratio decreased (P<0.01), intracellular SOD activity decreased and MDA content increased (P<0.01), the proportion of cleaved caspase-3, Cyto C and Bax/Bcl-2 were increased (P<0.01). Compared with H2O2-treated group, the survival rate of cells in broccoli polypeptide component II- pretreated groups was increased significantly (P<0.01), the apoptosis rate was decreased significantly (P<0.01). The SOD activity increased and MDA concentration decreased (P<0.01). The expression of intracellular cleaved caspase-3, Cyto C and Bax/Bcl-2 were decreased (P<0.01). CONCLUSION: Broccoli polypeptide component II has protective effect on hydrogen peroxide-induced vascular endothelial cells apoptosis and the possible mechanism may be associated with protection the function of mitochondrion.