Protective effect of procyanidin B2 on hydrogen peroxide (H2O2)-induced oxidative damage in MCF-7 cells

Abstract

The aim of this study is to assess the cytoprotection and potential molecular mechanisms of procyanidin B₂ (PCB₂) on hydrogen peroxide (H₂O₂)-induced oxidative damage in MCF-7 cells. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was performed to determine the viability of MCF-7 cell exposure to H₂O₂ or PCB₂. We measured the antioxidant properties of PCB₂ by determining the activities of SOD, GSH-Px, LDH and MDA levels, and evaluated apoptosis and intracellular reactive oxygen species (ROS) levels. The related proteins expression levels were monitored by Western blot. MCF-7 cells induced with H₂O₂ had a remarkable decrease in cell viability that was suppressed when it was interfered with PCB₂ (0.1–10.0 μM). PCB₂ interference memorably and dose-dependently inhibited H₂O₂-induced LDH leakage, ROS and MDA overproduction, while PCB₂ markedly increased H₂O₂-induced the activities of SOD and GSH-Px. Eventually, H₂O₂ prominently down-regulated the ratio of Bcl-2/Bax and the relative proteins expression levels of Nrf2, GCLC, NQO1 and HO-1, and up-regulated the relative proteins expression levels of cytochrome c, caspase-3 and Keap1. However, the relative expression levels of these proteins were reversed in PCB₂-interfered MCF-7 cells. This study implied that protective effect of PCB₂ on H₂O₂-induced oxidative damage in MCF-7 cells might be related to inhibition of mitochondria-dependent apoptosis, activation of Keap1/Nrf2/HO-1 signaling pathway and improvement of the antioxidant enzymes activities.