Intermittent Hypoxia Protects Brain from Ethanol Withdrawal Mechanisms and Therap

描述(由申请人提供)：停止酒精消耗是困难的，而且往往不成功，即使对积极性很高的患者也是如此。突然停止接触酒精会使大脑容易出现神经后遗症，包括感觉运动障碍、震颤和抽搐，这些都会阻碍患者停止饮酒的努力。乙醇戒断(EW)痛苦的唯一有效治疗方法是苯二氮卓类药物，但其副作用(如依赖和呼吸抑制)限制了该治疗方法的临床应用。在乙醇中毒和戒断的大鼠模型中，我们最近通过每天5-10分钟的间歇性、常压、中度(FiO2 9.5-10%)低氧(IH)证明了显著的脑保护作用。在我们的初步研究中，当在酒精饮食的最后20天应用IH治疗时，它减轻了EW的明显行为体征(例如震颤和僵硬)、EW诱导的线粒体膜肿胀和细胞毒性。特别是，EW使促凋亡蛋白P38增加了6倍以上；在酒精戒断的大鼠中，IH条件处理几乎完全抑制了这种增加。有趣的是，所有这些IH保护在EW期间都比在酒精暴露期间更有效，这意味着IH抵消了介导EW的因素。这些显着的结果表明，适应间歇性常压低氧可以提供一种安全有效的治疗方法，补充传统的苯二氮卓类药物。使用重复戒断范式，我们打算定义IH保护的行为表型与IH的不同治疗窗口以及涉及P38的细胞机制，IH通过该机制保护免受重复的EW。我们假设，在EW的初始周期中应用的IH条件反射在重复的EW过程中对行为和脑损伤具有持久的保护作用。大鼠将接受两个周期的乙醇饮食(7.5%)，为期5周，并突然停用20天。IH条件作用将应用于电子战的初始周期或乙醇暴露阶段。我们将确定1)在EW的初始周期中进行IH治疗是否可以防止明显的EW行为迹象和小脑/海马体相关的行为缺陷，以及这种保护是否持续到重复的EW；2)IH诱导的P38活性抑制是否介导了对凋亡(程序性细胞死亡)脑损伤的保护，以及这种保护是否以与行为保护相关的方式持续到EW的整个过程。一些动物将接受P38抑制剂SB203580来确定P38抑制在IH保护中的作用。定义针对EW侮辱的IH诱导的行为和脑保护并确定最佳治疗窗口可以为开发EW的替代治疗建立必要的基础数据。 公共卫生相关性：由于与突然停止饮酒相关的痛苦，酗酒者未能实现完全戒酒。我们观察到，间歇性短暂(5到8分钟)和中度低氧(9%到10%氧气)的循环训练减少了大鼠酒精戒断的迹象(如震颤和僵硬)和氧化应激。有关间歇性低氧引起的脑保护作用于酒精戒断痛苦的信息将为最终的临床应用奠定经验基础，从而更好地管理酒精中毒，而酒精戒断在其中起着关键作用。

DESCRIPTION (provided by applicant): The cessation of ethanol consumption is difficult and often unsuccessful, even for highly motivated patients. Abrupt termination of ethanol-exposure renders the brain vulnerable to neurological sequelae, including sensorimotor impairment, tremor, and convulsions, which discourage the patient's efforts to stop consuming alcohol. The only available treatment for the ethanol withdrawal (EW) distress is benzodiazepines but the side effects (e.g. dependency and respiratory depression) limit clinical use of this treatment. In a rat model of ethanol intoxication and withdrawal, we recently demonstrated profound brain protection by daily cycles of 5-10 minutes, intermittent, normobaric, moderate (FIO2 9.5-10%) hypoxia (IH). In our pilot studies, when IH treatment was applied during the last 20 days of an ethanol diet, it attenuated the overt behavioral signs of EW (e.g. tremor and rigidity); EW-induced mitochondrial membrane swelling; and cytotoxicity. In particular, EW provoked a more than 6-fold increase in the proapoptotic kinase P38; IH conditioning almost completely suppressed this increase in ethanol withdrawn rats. Interestingly, all of these IH protections were more effective during EW than during ethanol-exposure, implicating that IH counteracts factors mediating EW. These remarkable results suggest that adaptation to intermittent normobaric hypoxia could provide a safe and effective treatment complementary to conventional benzodiazepines. Using a repeated withdrawal paradigm, we intend to define behavioral phenotypes of IH protection with various treatment windows of IH and cellular mechanisms involving P38 by which IH protects against repeated EW. We hypothesize that IH conditioning applied during the initial cycle of EW exerts persistent protection against behavioral and brain injury throughout repeated EW. Rats will receive two cycles of an ethanol diet (7.5%) for 5 weeks and abrupt withdrawal for 20 days. IH conditioning will be applied to the initial cycle of the EW or the ethanol-exposure phase. We will determine 1) whether IH treatment during the initial cycle of EW protects against overt behavioral signs of EW and cerebellum-/hippocampus-related behavioral deficit and whether the protection persists throughout the repeated EW; 2) whether IH-induced suppression of P38 activity mediates protection against apoptotic (programmed cell death) brain injury and whether the protection persists throughout the repeated EW in a manner that correlates with behavioral protection. Some animals will receive the P38 inhibitor SB203580 to define the role of P38-inhibition in the IH protection. Defining the IH-induced behavioral and brain protection against EW insults and identifying an optimal treatment window may establish foundation data necessary for the development of an alternative management of EW. PUBLIC HEALTH RELEVANCE: Alcoholics failed to achieve complete abstinence due to distress associated with sudden termination of drinking. We observed that cycles of intermittent brief (5 to 8 min) and moderate hypoxia (9 to 10% oxygen) conditioning reduced signs of ethanol withdrawal (e.g. tremor and rigidity) and oxidative stress in rats. Information on intermittent hypoxia-evoked brain protection from ethanol withdrawal distress resulting will establish an empirical foundation to support eventual clinical application for a better management of alcoholism in which ethanol withdrawal plays a key role.