Low-level Laser Therapy in Global Cerebral Ischemia

描述（由申请人提供）：心脏骤停期间的短暂性全脑缺血（GCI）每年影响30万美国人，在许多情况下，导致海马CA 1神经元延迟死亡和严重的认知缺陷。目前的治疗方法是无效的，只能提供很短的治疗窗口。低水平激光/光疗法（LLLT）通过直接将低能量激光或发光二极管（LED）应用于身体上感兴趣的特定区域而被广泛实践。作为一种非侵入性手术，激光/光可以穿透动物头骨和大脑到2.5-3 cm的深度。我们在GCI动物模型中的初步工作表明，GCI后3小时LLLT强烈保护CA 1锥体区域。这一令人兴奋的观察结果带来了希望，对GCI后LLLT神经保护机制的进一步研究可能会导致人类的新疗法，这将允许在心脏骤停后以延长的治疗窗口拯救人脑中的海马CA 1神经元。当前提案的总体目标是描绘LLLT益处的最佳波长、剂量和时间窗，并阐明LLLT如何在GCI后保护大脑。我们假设脑缺血再灌注诱导ROS的产生和ATP超载从功能障碍的线粒体神经元。这导致随后增强的氧化损伤和NLRP 3炎性级联信号传导，导致延迟的CA 1神经元死亡和认知缺陷。LLLT能够保持线粒体完整性和膜电位，阻断ROS产生和ATP过载。我们提出LLLT刺激源自大肠杆菌的一氧化氮（NO）释放以抑制NLRP 3炎性体的激活（通过NLRP 3的S-亚硝基化）并激活Nrf 2（通过Keap 1的S-亚硝基化和Nrf 2释放）。我们进一步假设LLLT可以通过促进Nrf 2调节的基因表达（例如Trx和SOD 2）来抵消NLRP 3炎性体级联反应和GCI后由功能失调的线粒体诱导的氧化损伤来发挥其有益作用。拟议的临床前研究将通过成为第一个确定LLLT在GCI后保护大脑的潜在功效来推进该领域。具体目标1将检验LLLT在GCI后发挥神经保护作用并改善功能结局的假设。具体目标2将检验LLLT通过激活GCI后的Nrf 2通路减少缺血性氧化损伤和功能缺陷的假设。第3章测试 LLLT通过保护线粒体完整性和促进Nrf 2调节的基因表达来防止NLRP 3炎性小体活化的假设。

DESCRIPTION (provided by applicant): Transient global cerebral ischemia (GCI) during cardiac arrest affects 300,000 Americans each year, and in many cases, results in delayed death of hippocampal CA1 neurons and severe cognitive deficits. Current therapies are ineffective and only offer a short therapeutic window. Low-level Laser/Light Therapy (LLLT) is widely practiced by directly applying a low energy laser or light emitting diodes (LED) to a specific area of interest on the body. As a noninvasive procedure, the laser/light can penetrate the animal skull and brain to a depth of 2.5-3 cm. Our preliminary work in the GCI animal model has shown that LLLT 3 h after GCI strongly protects the CA1 pyramidal regions. This exciting observation has led to hope that further studies on the mechanisms underlying LLLT neuroprotection following GCI could potentially lead to new therapies in humans, which would allow rescue of hippocampal CA1 neurons in the human brain following cardiac arrest with an extended therapeutic window. The overall goal of the current proposal is to delineate the optimal wavelengths, doses, and time window of LLLT benefits, and to elucidate how LLLT protects the brain following GCI. We hypothesize that cerebral ischemic reperfusion induces ROS production and ATP overloading from dysfunctional mitochondria in neurons. This leads to subsequent enhanced oxidative damage and NLRP3 inflammasome cascade signaling, resulting in delayed CA1 neuronal death and cognitive deficits. LLLT is able to preserve mitochondrial integrity and membrane potential, blocking ROS production and ATP overloading. We propose that LLLT stimulates mitochondria-derived nitric oxide (NO) release to inhibit the activation of NLRP3 inflammasome (via S-nitrosylation of NLRP3) and to activate Nrf2 (via S-nitrosylation of Keap1 and Nrf2 release). We further hypothesize that LLLT can exert its beneficial actions by boosting Nrf2-regulated gene expression (e.g. Trx and SOD2) to counteract the NLRP3 inflammasome cascade and the oxidative damage induced by dysfunctional mitochondria after GCI. The proposed preclinical studies would advance the field by being the first to determine the potential efficacy of LLLT for protection of the brain following GCI. Specific Aim 1 would test the hypothesis that LLLT exerts neuroprotection and improves functional outcome after GCI. Specific Aim 2 would test the hypothesis that LLLT reduces ischemic oxidative damage and functional deficits via the activation of the Nrf2 pathway following GCI. Specific Aim 3 would test the hypothesis that LLLT prevents NLRP3 inflammasome activation by preserving mitochondrial integrity and promoting Nrf2-regulated gene expression.