Babsky Andriy, Hekmatyar Shahryar, Wehrli Suzanne, Doliba Nicolai, Osbakken Mary, Bansal Navin
Department of Radiology, 207 Anatomy-Chemistry Building, University of Pennsylvania, 37th and Hamilton Walk, Philadelphia, PA 19104, USA.
Exp Biol Med (Maywood). 2002 Jul;227(7):520-8. doi: 10.1177/153537020222700717.
The possible relationships between intracellular Na(+) (Na(i)(+)), bioenergetic status and intracellular pH (pH(i)) in the mechanism for ischemic preconditioning were studied using (23)Na and (31)P magnetic resonance spectroscopy in isolated Langendorff perfused rat heart. The ischemic preconditioning (three 5-min ischemic episodes followed by two 5-min and one 10-min period of reperfusion) prior to prolonged ischemia (20 min stop-flow) resulted in a decrease in ischemic acidosis and faster and complete recovery of cardiac function (ventricular developed pressure and heart rate) after 30 min of reperfusion. The response of Na(i) during ischemia in the preconditioned hearts was characterized by an increase in Na(i)(+) at the end of preconditioning and an accelerated decrease during the first few minutes of reperfusion. During post-ischemic reperfusion, bioenergetic parameters (PCr/P(i) and betaATP/P(i) ratios) were partly recovered without any significant difference between control and preconditioned hearts. The reduced acidosis during prolonged ischemia and the accelerated decrease in Na(i)(+) during reperfusion in the preconditioned hearts suggest activation of Na(+)/H(+) exchanger and other ion transport systems during preconditioning, which may protect the heart from intracellular acidosis during prolonged ischemia, and result in better recovery of mechanical function (LVDP and heart rate) during post-ischemic reperfusion.
利用（23）Na和（31）P磁共振波谱技术，在离体Langendorff灌注大鼠心脏中研究了缺血预处理机制中细胞内Na⁺（Na(i)⁺）、生物能量状态和细胞内pH（pH(i)）之间可能的关系。在长时间缺血（20分钟停流）之前进行缺血预处理（三次5分钟缺血发作，随后是两次5分钟和一次10分钟的再灌注期），可导致缺血性酸中毒减轻，再灌注30分钟后心脏功能（心室舒张末压和心率）恢复更快且更完全。预处理心脏在缺血期间Na(i)的反应特征是预处理结束时Na(i)⁺增加，再灌注最初几分钟内加速下降。在缺血后再灌注期间，生物能量参数（PCr/P(i)和βATP/P(i)比值）部分恢复，对照组和预处理心脏之间无显著差异。预处理心脏在长时间缺血期间酸中毒减轻以及再灌注期间Na(i)⁺加速下降，提示预处理期间Na⁺/H⁺交换器和其他离子转运系统被激活，这可能保护心脏在长时间缺血期间免受细胞内酸中毒影响，并导致缺血后再灌注期间机械功能（左室舒张末压和心率）更好地恢复。
