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.

中文翻译：

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原花青素B ₂对过氧化氢（H ₂ O ₂）诱导MCF-7细胞氧化损伤的保护作用

这项研究的目的是评估原花青素B2（PCB2）对过氧化氢（H2O2）诱导的MCF-7细胞氧化损伤的细胞保护作用和潜在的分子机制。进行3-（4,5-二甲基噻唑-2-基）-2,5-二苯基四唑溴化物（MTT）测定以确定MCF-7细胞暴露于H2O2或PCB2的活力。我们通过确定SOD，GSH-Px，LDH和MDA的活性来测量PCB2的抗氧化性能，并评估细胞凋亡和细胞内活性氧（ROS）的水平。通过蛋白质印迹监测相关蛋白的表达水平。H2O2诱导的MCF-7细胞的细胞活力显着下降，当它受到PCB2的干扰时（0.1–10.0μM）受到抑制。PCB2可以显着且剂量依赖性地抑制H2O2诱导的LDH泄漏，ROS和MDA的过量产生，而PCB2显着增加H2O2诱导SOD和GSH-Px的活性。最终，H2O2显着下调了Bcl-2 / Bax的比例以及Nrf2，GCLC，NQO1和HO-1的相对蛋白表达水平，并上调了细胞色素c，caspase-3和Keap1的相对蛋白表达水平。 。但是，这些蛋白质的相对表达水平在PCB2干扰的MCF-7细胞中被逆转。这项研究表明，PCB2对H2O2诱导的MCF-7细胞氧化损伤的保护作用可能与抑制线粒体依赖性细胞凋亡，激活Keap1 / Nrf2 / HO-1信号通路和改善抗氧化酶活性有关。H2O2显着下调Bcl-2 / Bax的比例以及Nrf2，GCLC，NQO1和HO-1的相对蛋白表达水平，并上调细胞色素c，caspase-3和Keap1的相对蛋白表达水平。但是，这些蛋白质的相对表达水平在PCB2干扰的MCF-7细胞中被逆转。这项研究表明，PCB2对H2O2诱导的MCF-7细胞氧化损伤的保护作用可能与抑制线粒体依赖性细胞凋亡，激活Keap1 / Nrf2 / HO-1信号通路和改善抗氧化酶活性有关。H2O2显着下调Bcl-2 / Bax的比例以及Nrf2，GCLC，NQO1和HO-1的相对蛋白表达水平，并上调细胞色素c，caspase-3和Keap1的相对蛋白表达水平。但是，这些蛋白质的相对表达水平在PCB2干扰的MCF-7细胞中被逆转。这项研究表明，PCB2对H2O2诱导的MCF-7细胞氧化损伤的保护作用可能与抑制线粒体依赖性细胞凋亡，激活Keap1 / Nrf2 / HO-1信号通路和改善抗氧化酶活性有关。