Stilbene's Contribution in Hemorrhagic Stroke

描述（由申请人提供）：二苯乙烯化合物白藜芦醇天然存在于葡萄皮和葡萄籽中，在红酒中含量特别高。流行病学研究表明，喝红酒的人患血管疾病的风险较低，这一现象被称为法国悖论。本研究表明，白藜芦醇预处理可降低缺血性卒中损伤。神经退行性疾病中的神经元细胞死亡被认为是由自由基损伤介导的。有希望限制自由基介导的损伤的候选者是存在于中枢神经系统的内源性抗氧化酶，如过氧化氢酶、超氧化物歧化酶和血红素加氧酶。这些细胞保护蛋白的转录受Nrf2的控制，Nrf2在细胞氧化还原状态的调节中起着核心作用。例如，我们和其他研究人员发现，血红素加氧酶具有保护作用，它能将促氧化血红素分解成胆汁素/胆红素（抗氧化剂）。一个目标是诱导它，在我们测试的化合物中，如初步数据所示，白藜芦醇是最有效的诱导剂。我们的初步数据表明，用白藜芦醇预处理神经元足以提供神经保护，这表明氧化应激期间的共处理是不必要的。到目前为止的结果表明，Nrf2控制下的基因特异性诱导可能是白藜芦醇在中风中发挥其神经保护作用的一种机制。我们将继续研究口服白藜芦醇预处理对出血性中风的有益作用，并确定它是否能降低胶原酶和脑出血（ICH）自体血模型小鼠结局的严重程度。我们将研究急性和慢性每日口服白藜芦醇对出血后不同时间点脑损伤体积、脑水肿和神经行为结果缺陷的影响，并测试Nrf2敲除小鼠中这些有益作用是否减弱。为了进一步确定白藜芦醇是否对神经元具有保护作用，并解决可能的细胞作用机制，将Nrf2敲除幼崽和匹配对照的出生后培养的初级神经元进行白藜芦醇预处理，然后测试对叔丁基过氧化氢诱导的自由基毒性和血红素（也是一种促氧化剂）的敏感性。值得注意的是，在脑出血等病理条件下，血红素达到高毒性水平；它不能回收，必须被降解。Nrf2可以诱导多种抗氧化酶。这些结果将表明初级神经元的预处理是否足以提供神经保护，以及Nrf2是否调节了这种作用。了解白藜芦醇等天然化合物在缺血性和出血性中风中的功效和局限性/安全性，可能有助于公众和医疗保健提供者做出明智的决定，确定白藜芦醇和类似的生物活性提取物是否有效地作为这种毁灭性神经系统疾病的辅助治疗。这也将使我们能够解决可能的机制，通过口服苯乙烯白藜芦醇可能具有神经保护作用，并有可能为大脑提供细胞内源性抵抗衰弱性神经退行性疾病的能力。

DESCRIPTION (provided by applicant): The stilbene compound resveratrol is naturally present in grape skin and seeds and is found in particularly high concentrations in red wine. Epidemiological studies have shown that those who consume red wine have a reduced risk of vascular diseases, a phenomenon known as the French Paradox. Here, we document that pretreatment with resveratrol decreases ischemic stroke damage. Neuronal cell death in neurodegenerative conditions has been postulated to be mediated by free radical damage. Promising candidates to limit free radical-mediated damage are the endogenous antioxidant enzymes present in the central nervous system, such as catalase, superoxide dismutases, and heme oxygenases. Transcription of these cytoprotective proteins is under control of Nrf2, which plays a central role in the regulation of the cellular redox status. For example, we and other showed that heme oxygenase enzyme, which cleaves the prooxidant heme to form biliverdin/bilirubin (antioxidants), is protective. One goal would be to induce it, and of the compounds we tested, as shown in the preliminary data, resveratrol was a most potent inducer. Our preliminary data indicate that pretreatment of neurons with resveratrol was sufficient to provide neuroprotection, suggesting that cotreatment during oxidative stress is not necessary. The results so far imply that specific induction of genes under the control of Nrf2 could be a mechanism by which resveratrol exerts its neuroprotective actions in stroke. We will extend our ongoing inquiry into the beneficial effects of oral pretreatment with resveratrol against hemorrhagic stroke and determine whether it can reduce the severity of outcomes in mice subjected to the collagenase and autologous blood models of intracerebral hemorrhage (ICH). We will investigate the effect of acute and chronic daily oral administration of resveratrol on brain injury volume, brain edema, and neurobehavioral outcome deficits at different time points following hemorrhage and test whether these beneficial effects are attenuated in Nrf2 knockout mice. To further determine if resveratrol of protective in neurons and address possible cellular mechanisms of action, primary postnatal cultured neurons derived from Nrf2 knockout pups and matched controls will be pretreated with resveratrol and then tested for susceptibility to tert- butylhydroperoxide-induced free radical toxicity and heme, which is also a pro-oxidant. Notably, under pathologic conditions such as in ICH, heme reaches high toxic levels; it cannot be recycled and has to be degraded. Nrf2 can then induce various antioxidant enzymes. These results will indicate whether preconditioning of primary neurons is sufficient to afford neuroprotection and whether the effect is modulated by Nrf2. Understanding the efficacy and limitations/safety of natural compounds such as resveratrol in ischemic and hemorrhagic stroke may help the general public and healthcare providers to make informed decisions on whether resveratrol and similar bioactive extracts are efficacious as adjunct treatments for such devastating neurological diseases. It will also allow us to address possible mechanisms by which the oral consumption of the stilbene resveratrol could be neuroprotective and have the putative ability to provide the brain with cellular endogenous resistance to debilitating neurodegenerative conditions. PUBLIC HEALTH RELEVANCE: For decades, the stilbene resveratrol and red wine have been suggested as preventive medicine to strengthen the heart and the brain, but the underlying cellular mechanisms are still unclear. Our preliminary results prompted us to focus our attention on resveratrol and test the hypothesis that the pathway leading to the regulation of the transcriptional factor Nrf2 could participate in resveratrol's neuroprotective function. Using preclinical laboratory mouse models, we will determine whether prophylactic consumption of resveratrol can prevent neurological decline and brain damage following hemorrhagic stroke, thus providing new pathways by which resveratrol could provide resistance to acute neurological disorders.