Hyperbaric oxygen therapy mitigates respiratoryneuromuscular pathology after spinal cord injury

摘要 高压氧治疗包括在≤3大气压下短暂(≤1小时)暴露在加压氧中，并使用 常用于伤口愈合和减压病。我们的初步数据和文献报告显示 对于中心假设，高压氧是在颈髓损伤后的急性期(几天到几周)交付的 (脊髓损伤)，减轻横隔膜萎缩和功能障碍，减轻颈髓病理，并改善 呼吸性神经肌肉恢复。高压氧治疗与抗高血压之间的机制联系 脊髓损伤后的肌肉和神经病理均为氧化应激。初步数据显示，宫颈 挫伤导致隔膜内ROS的显著增加和萎缩。初步测试也包括 结果显示，高压氧治疗1小时，10天后，横隔膜ROS形成减少，横隔膜增加 抗氧化能力。高压氧治疗也大大减轻了萎缩和收缩损伤。 发生在颈部挫伤之后。关于脊髓神经病理学，继发性损伤(即病理学 在最初的创伤后发展)损害了运动的恢复。初步的组织学和分子数据 显示高压氧在减少颈部挫伤继发性损伤的神经保护作用 脊髓。这包括随着凋亡标志物表达的减少和减少而减少的神经元丢失 高压氧治疗后的炎症。由于氧化应激导致二次损伤，我们预测HBO- 诱导的抗氧化剂表达上调是这些效应的基础。总的来说，保存下来的横隔膜 功能和减弱的宫颈病理导致我们的总体假设是呼吸恢复将是 通过HBO治疗得到改善。目标1将验证高压氧治疗在急性到亚急性期间的假设 颈椎脊髓损伤后各时相可减少横隔膜萎缩，改善收缩能力。这一假设将得到检验。 对横隔膜进行组织学、分子和功能评价。为了测试氧化机制，反义 在HBO治疗期间，寡核苷酸将被用来阻止特定抗氧化剂的翻译。要确定是否 抗氧化机制足以解释高压氧的治疗效果，我们将过度表达特定的 抗氧化剂使用腺相关病毒(AAV)。目标2将检验神经保护影响的假设 颈椎脊髓损伤后急性期和亚急性期高压氧治疗可改善膈运动 恢复。这一假说将通过组织学、分子和神经生理学方法进行检验(直接 膈神经记录和隔膜肌电图术)。与目标1一样，机械论研究将利用 反义寡核苷酸和AAV策略调节脊髓中抗氧化剂的形成。共同派博士。 斯穆德是横隔膜生物学和萎缩机制方面的专家。共同派富勒博士有丰富的经验 在呼吸功能障碍的临床前脊髓损伤模型中。咨询顾问迪恩博士是HBO的权威。

ABSTRACT Hyperbaric oxygen (HBO) therapy involves brief (≤1 hr) exposure to pressurized oxygen at ≤3 ATM and is used frequently for wound healing and decompression sickness. Our preliminary data and literature reports have led to the central hypothesis that HBO, delivered in the acute phases (days to weeks) after cervical spinal cord injury (SCI), attenuates diaphragm atrophy and dysfunction, reduces cervical spinal cord pathology, and improves respiratory neuromuscular recovery. The proposed mechanistic link between HBO therapy and attenuation of both muscular and neural pathology after SCI is oxidative stress. Preliminary data demonstrate that cervical contusion injury leads to substantial increases in ROS in the diaphragm and atrophy. Preliminary testing also showed that 1 hr HBO therapy for 10 days decreased diaphragm ROS formation and increased diaphragm antioxidant capacity. The HBO therapy also considerably attenuated the atrophy and contractile impairments that occurred after cervical contusion. In regards to spinal neuropathology, secondary damage (i.e., pathology that develops after the initial trauma) impairs motor recovery. Preliminary histological and molecular data demonstrate a neuroprotective impact of HBO with reduction in secondary damage in the contused cervical spinal cord. This includes attenuated neuronal loss with reduced expression of apoptotic markers and reduced inflammation after HBO therapy. Since oxidative stress contributes to secondary damage, we predict that HBO- induced upregulation of antioxidant expression underlies these effects. Collectively, the preserved diaphragm function and attenuated cervical pathology lead to our overall hypothesis that respiratory recovery will be improved by HBO therapy. Aim 1 will test the hypothesis that HBO therapy during acute through sub-acute phases after cervical SCI reduces diaphragm atrophy and improves contractility. The hypothesis will be tested with histological, molecular and functional evaluation of the diaphragm. To test oxidative mechanisms, antisense oligonucleotides will be used to block translation of specific antioxidants during HBO therapy. To determine if antioxidant mechanisms are sufficient to explain the HBO therapeutic effects, we will overexpress specific antioxidants using adeno-associated virus (AAV). Aim 2 will test the hypothesis that the neuroprotective impact of HBO therapy during acute through sub-acute phases after cervical SCI leads to improved phrenic motor recovery. The hypothesis will be tested with histological, molecular, and neurophysiological methods (direct phrenic nerve recordings and diaphragm electromyography). As in Aim 1, mechanistic studies will utilize antisense oligonucleotides and AAV strategies to modulate antioxidant formation in the spinal cord. Co-PI Dr. Smuder is an expert in diaphragm biology and mechanisms of atrophy. Co-PI Dr. Fuller has extensive experience in preclinical SCI models of respiratory dysfunction. Consultant Dr. Dean is an authority on HBO.