Nrf2通路在氢治疗急性CO中毒迟发性脑病中的作用及机制

Patients with severe carbon monoxide (CO) poisoning may also leave delayed neurologic sequelae(DNS),even save a life after positive treatment.The pathogenesis of DNS is not clear, some researchers have put forward the doctrine of oxidative damage,in the process of which antioxidant enzyme system is an important defense. It is reported that Nrf2 is an important antioxidant transcription factors in vivo, which plays an important role in Parkinson's disease,Alzheimer's disease.But its role in the DNS is unknown. Recent studies showed that hydrogen has a therapeutic effect on cerebral ischemia-reperfusion injury, Parkinson's disease, Alzheimer's disease through antioxidant and anti-inflammatory. In previous work, we found that hydrogen-rich saline played neuroprotective role in acute carbon monoxide poisoning.Studies prefered that hydrogen upregulated Nrf2. On the basis of these findings, we speculated that hydrogen-rich saline may reduces DNS in experimental carbon monoxide toxicity through increasing the Nrf2 expression and its DNA binding activity in the brain, inducing downstream oxidation protein expression.This project is based on the previous research, focusing on the Nrf2, to detect Nrf2 mRNA and protein expression and transcriptional activity.Also we will observe these change after blocking or agitating Nrf2 during hydrogen-rich saline therapy in DNS of carbon monoxide toxicity. Through the implementation of this project, we intend to clarify the mediating mechanism of Nrf2/ARE signaling pathway in the protection of hydrogen-rich saline on DNS,thus provide new agent for clinical prevention and treatment of DNS.

重症一氧化碳(CO)中毒患者经救治后即使存活，也常留下棘手的迟发性神经精神后遗症，如迟发性脑病(DNS)。目前其发病机制比较公认的是氧化损伤学说。氧化损伤过程中抗氧化酶是生物体的重要防线，而Nrf2是重要的抗氧化转录因子，研究表明它在帕金森病、阿尔茨海默病等脑病中起着重要的作用，但其在DNS中的作用尚无报道。近期研究显示，氢通过抗氧化、抗炎作用对脑缺血再灌注损伤、帕金森病等具有治疗作用。我们发现富氢水对急性CO中毒脑损伤具有保护作用。研究证实氢在体内具有上调Nrf2的作用。因此，我们推测氢可能通过增加脑内Nrf2表达，诱导下游抗氧化蛋白表达上调，对DNS产生保护作用。本项目拟在前期研究基础上，以Nrf2为切入点，通过观察SOD、HO-1含量及Nrf2 mRNA和蛋白水平、转录活性，研究氢在DNS中的保护作用及Nrf2/ARE信号通路的介导机制，为临床预防和治疗DNS提供新的思路。

氢是自然界最轻、含量最丰富的化学元素，但是很少用于临床治疗使用。近年来的研究发现氢是潜在的抗氧化剂、具有抗凋亡和抗感染作用，在细胞、组织和器官具有广泛的医用价值。我们研究结果为富氢水对CO中毒后DNS的保护机制提供了依据：（1）Nrf2的目标靶基因是体内抗氧化最有效的系统，不需要补充抗氧化物质，就可以发挥作用，而且不会造成过度抗氧化。以Nrf2为治疗靶点用于DNS，相对于其它治疗方法，具有较好的安全性和实用性，有更广阔的临床应用前景；（2）本研究从体内和体外两个层面观察氢对Nrf2 基因和蛋白含量水平、转录活性和阻断后的变化，对急性CO中毒DNS及富氢水治疗后Nrf2 的生物学效应进行比较全面的研究。结果显示，富氢水腹腔注射或细胞培养，可通过提高Nrf2的核转位和上调下游抗氧化酶的表达，发挥神经保护作用。基于本研究的结果，富氢水有望成为一种临床上有效预防和治疗CO中毒DNS的方法。