Abstract: Objective To investigate the protective effect and mechanism of dl-3-n-butylphthalide (NBP) on hydrogen peroxide (H₂O₂) - induced oxidative damage of vascular endothelial cells (VECs). Methods Human umbilical vein endothelial cells (HUVECs) and human umbilical artery endothelial cells (HUAECs) were cultured and MTT assay was used to find the appropriate dosage of H₂O₂ for establishment of oxidative stress injury model. Then the cells were pre-incubated with two different dosages of NBP (5 and 10 μmol/L) 2 h before exposure to H₂O₂. The cell viability was detected by MTT assay, mitochondrial membrane potential was measured by rhodamine 123, cell apoptosis was detected by Annexin-V/PI double staining, and intracellular free Ca²⁺ was measured by Fura-4/AM. Results H₂O₂-induced oxidative injury reduced the cell viability of HUVECs and HUAECs, increased the intracellular free Ca²⁺ concentration thus leading to mitochondrial membrane potential decline and cell apoptosis(P＜0.05). However, NBP treatment improved the above changes induced by H₂O₂. Conclusions NBP protects vascular endothelial cells by alleviating the oxidative damage induced by H₂O₂.

Key words: oxidative stress, dl-3-n-butylphthalide, human umbilical vein endothelial cells, human umbilical artery endothelial cells