Department of Anatomy, Faculty of Medicine, University of Porto, 4200-319 Porto, Portugal.
Free Radic Biol Med. 2010 Mar 15;48(6):831-8. doi: 10.1016/j.freeradbiomed.2010.01.003. Epub 2010 Jan 11.
We previously found that prolonged consumption of green tea (GT), a rich source of antioxidant polyphenols, protected proteins and lipids against oxidation and reduced lipofuscin deposition in the rat hippocampal formation as well as improving spatial memory during aging. In this work, we sought to investigate whether GT treatment could interfere with age-related changes in redox status and cellular signaling systems related to oxidative stress and survival in the same brain region. To address this issue, five male Wistar rats were fed with GT from 12 to 19 months of age and results were compared to those obtained from controls age 19 months (C-19 M). A third group of rats was evaluated at 12 months of age to provide baseline data. At completion of the specified time points, the glutathione levels and antioxidant enzyme activities, the activation of the transcription factors cyclic AMP response element-binding (CREB) and nuclear factor-kappaB (NF-kappaB, p50 and p65 subunits), and the levels of brain-derived neurotrophic factor (BDNF) and B-cell lymphoma-2 (Bcl-2) were measured in hippocampal formations. GT-treated rats presented higher reduced and lower oxidized glutathione levels and displayed favorable alterations in antioxidant enzyme activities compared to C-19 M animals. In addition, GT increased CREB activation and the levels of BDNF and Bcl-2, but had no effect on activation of NF-kappaB subunits, relative to age-matched controls. We conclude that long-term GT ingestion improves antioxidant systems and activates CREB in the aging rat hippocampal formation, leading to neuroprotection mediated by downstream upregulation of BDNF and Bcl-2.
我们之前发现，长期饮用富含抗氧化多酚的绿茶（GT）可以保护蛋白质和脂质免受氧化，减少大鼠海马区脂褐素的沉积，并改善衰老过程中的空间记忆。在这项工作中，我们试图研究 GT 处理是否可以干扰与氧化应激和生存相关的氧化还原状态和细胞信号转导系统在同一脑区的年龄相关变化。为了解决这个问题，我们从 12 个月到 19 个月龄给五只雄性 Wistar 大鼠喂食 GT，并将结果与 19 个月龄的对照组（C-19 M）进行比较。第三组大鼠在 12 个月龄时进行评估，以提供基线数据。在规定的时间点完成后，测量海马区的谷胱甘肽水平和抗氧化酶活性、转录因子环磷酸腺苷反应元件结合（CREB）和核因子-κB（NF-κB，p50 和 p65 亚基）的激活以及脑源性神经营养因子（BDNF）和 B 细胞淋巴瘤-2（Bcl-2）的水平。与 C-19 M 动物相比，GT 处理的大鼠具有更高的还原型和更低的氧化型谷胱甘肽水平，并显示出有利的抗氧化酶活性变化。此外，与年龄匹配的对照组相比，GT 增加了 CREB 的激活以及 BDNF 和 Bcl-2 的水平，但对 NF-κB 亚基的激活没有影响。我们得出结论，长期 GT 摄入可改善衰老大鼠海马区的抗氧化系统并激活 CREB，从而通过下游 BDNF 和 Bcl-2 的上调介导神经保护。
