He Guanglong
The Center for Biomedical EPR Spectroscopy and Imaging, Davis Heart and Lung Research Institute and Division of Cardiovascular Medicine, Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, OH, USA.
Methods Mol Biol. 2010;594:85-105. doi: 10.1007/978-1-60761-411-1_6.
Reactive oxygen/nitrogen species (ROS/RNS) have been increasingly recognized as important mediators and play a number of critical roles in cell injury, metabolism, disease pathology, diagnosis, and clinical treatment. Electron paramagnetic resonance (EPR) spectroscopy enables the spectral information at certain spatial position, and, from the observed line-width and signal intensity, the localized tissue oxygenation, and tissue redox status can be determined. We applied in vivo EPR oximetry and redoximetry technique and implemented its physiological/pathophysiological applications, along with the use of biocompatible lithium pthalocyanine (liPc) and nitroxide redox sensitive probes, on in vivo tissue oxygenation and redox profile of the ischemic and reperfused heart in living animals. We have observed that the hypoxia during myocardial ischemia limited mitochondrial respiration and caused a shift of tissue redox status to a more reduced state. ROS/RNS generated at the beginning of reperfusion not only caused a shift of redox status to a more oxidized state which may contribute to the postischemic myocardial injury, but also a marked suppression of in vivo tissue O(2) consumption in the postischemic heart through modulation of mitochondrial respiration based on alterations in enzyme activity and mRNA expression of NADH dehydrogenase (NADH-DH) and cytochrome c oxidase (CcO). In addition, ischemic preconditioning was found to be able to markedly attenuate postischemic myocardial hyperoxygenation with less ROS/RNS generation and preservation of mitochondrial O(2) metabolism, due to conserved NADH-DH and CcO activities. These studies have demonstrated that EPR oximetry and redoximetry techniques have advanced to a stage that enables in-depth insight in the process of ischemia reperfusion injury.
活性氧/氮物种（ROS/RNS）已日益被视为重要的介质，并在细胞损伤、代谢、疾病病理、诊断和临床治疗中发挥着许多关键作用。电子顺磁共振（EPR）光谱能够获取特定空间位置的光谱信息，并且根据观察到的线宽和信号强度，可以确定局部组织的氧合作用以及组织的氧化还原状态。我们应用了体内EPR血氧测定法和氧化还原测定技术，并结合使用生物相容性酞菁锂（liPc）和氮氧化物氧化还原敏感探针，对活体动物缺血再灌注心脏的体内组织氧合作用和氧化还原特征进行了生理/病理生理应用研究。我们观察到，心肌缺血期间的缺氧限制了线粒体呼吸，并导致组织氧化还原状态向更还原的状态转变。再灌注开始时产生的ROS/RNS不仅导致氧化还原状态向更氧化的状态转变，这可能导致缺血后心肌损伤，而且还通过基于NADH脱氢酶（NADH-DH）和细胞色素c氧化酶（CcO）的酶活性和mRNA表达变化来调节线粒体呼吸，从而显著抑制缺血后心脏的体内组织O(2)消耗。此外，发现缺血预处理能够显著减轻缺血后心肌的高氧状态，减少ROS/RNS的产生，并由于NADH-DH和CcO活性的保留而维持线粒体O(2)代谢。这些研究表明，EPR血氧测定法和氧化还原测定技术已经发展到能够深入洞察缺血再灌注损伤过程的阶段。
