Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, 1 Youyi Road, Yuzhong District, Chongqing 400016, China.
Neurochem Res. 2011 Dec;36(12):2352-62. doi: 10.1007/s11064-011-0561-8. Epub 2011 Aug 18.
Oxidative stress damage plays a vital role in cerebral ischemia/reperfusion (I/R) pathogenesis. The nuclear factor erythroid 2-related factor 2 (Nrf2)/antioxidant response element (ARE) signaling pathway can be activated by pharmacological and dietary means to attenuate cellular oxidative stress. Resveratrol, a plant-derived polyphenolic compound, has antioxidant property. Recent studies have demonstrated that resveratrol has protective effects against cerebral I/R injury. However, little is known about its mechanism. Hence, this study identified the neuroprotective effect of resveratrol pretreatment and elucidate the Nrf2/ARE signaling mechanism after focal cerebral I/R injury in rats. Adult male Sprague-Dawley rats were randomly assigned to sham-operated group, ischemia/reperfusion physiological saline-treated group, and ischemia/reperfusion resveratrol-pretreatmented (15 and 30 mg/kg) groups. Rats were pretreatmented with resveratrol or physiological saline of corresponding volume administered intraperitoneally for 7 days before surgery and 30 min before middle cerebral artery occlusion. At 24 h after reperfusion, neurological score, infarct volume, and brain water content were assessed. Oxidative stress was evaluated by malondialdehyde (MDA) levels and superoxide dismutase (SOD) activity. Pathological changes of brain tissue were observed by HE staining. RT-PCR and Western blot analysed the expression of nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1). TUNEL staining detected apoptotic cells. The protein expression of Caspase-3 were studied by immunohistochemistry. Resveratrol pretreatment significantly ameliorated neurological scores, reduced infarct volume and brain water content, decreased MDA levels, restored the SOD activity, upregulated the protein and mRNA expression of Nrf2 and HO-1, downregulated the protein expression of caspase-3. TUNEL-positive cells significantly decreased compared with the physiological saline-treated group. HE staining also showed that resveratrol significantly improved neuronal injury. These results showed that resveratrol pretreatment had neuroprotective effects on cerebral I/R injury. This neuroprotective effect is likely exerted by upregulated expression of transcription factor Nrf2 and HO-1 to ameliorate oxidative damage, decreased the protein expression of caspase-3. Our finding is important for understanding the neuroprotective mechanism of resveratrol and promoting its clinical therapeutic utility.
氧化应激损伤在脑缺血/再灌注（I/R）发病机制中起着至关重要的作用。核因子红细胞 2 相关因子 2（Nrf2）/抗氧化反应元件（ARE）信号通路可通过药理学和饮食手段激活，以减轻细胞氧化应激。白藜芦醇是一种植物来源的多酚化合物，具有抗氧化特性。最近的研究表明，白藜芦醇对脑 I/R 损伤具有保护作用。然而，其机制知之甚少。因此，本研究旨在确定白藜芦醇预处理的神经保护作用，并阐明大鼠局灶性脑 I/R 损伤后 Nrf2/ARE 信号机制。成年雄性 Sprague-Dawley 大鼠随机分为假手术组、缺血/再灌注生理盐水处理组和缺血/再灌注白藜芦醇预处理（15 和 30mg/kg）组。大鼠在手术前 7 天和大脑中动脉闭塞前 30 分钟通过腹腔内给予白藜芦醇或相应体积的生理盐水预处理。再灌注后 24 小时，评估神经评分、梗死体积和脑水含量。通过丙二醛（MDA）水平和超氧化物歧化酶（SOD）活性评估氧化应激。通过 HE 染色观察脑组织的病理变化。RT-PCR 和 Western blot 分析核因子红细胞 2 相关因子 2（Nrf2）和血红素加氧酶-1（HO-1）的表达。TUNEL 染色检测凋亡细胞。免疫组化研究 Caspase-3 的蛋白表达。白藜芦醇预处理可显著改善神经评分，减少梗死体积和脑水含量，降低 MDA 水平，恢复 SOD 活性，上调 Nrf2 和 HO-1 的蛋白和 mRNA 表达，下调 caspase-3 的蛋白表达。与生理盐水处理组相比，TUNEL 阳性细胞明显减少。HE 染色也表明白藜芦醇可显著改善神经元损伤。这些结果表明，白藜芦醇预处理对脑 I/R 损伤具有神经保护作用。这种神经保护作用可能是通过上调转录因子 Nrf2 和 HO-1 的表达来改善氧化损伤，降低 caspase-3 的蛋白表达来实现的。我们的发现对于理解白藜芦醇的神经保护机制和促进其临床治疗应用具有重要意义。
