Garcia L A, Dejong S C, Martin S M, Smith R S, Buettner G R, Kerber R E
Cardiovascular Center and the Electron Spin Resonance Facility, The University of Iowa, Iowa City, USA.
J Am Coll Cardiol. 1998 Aug;32(2):536-9. doi: 10.1016/s0735-1097(98)00231-9.
This study demonstrated that magnesium (Mg) reduces free radicals after a brief coronary occlusion-reperfusion sequence.
Magnesium has been shown to reduce infarct size in patients with acute myocardial infarction. We hypothesized that this action of Mg occurs through its action on free radicals.
Eighteen mongrel dogs were studied (nine control, nine receiving Mg). Catheters were placed into the coronary sinus for continuous blood withdrawal. A Varian E-4 electron paramagnetic resonance spectrometer was used to monitor the ascorbate free radical (AFR) signal in the coronary sinus blood; AFR is a measure of total oxidative stress. Occlusion of the left anterior descending coronary artery for 20 min was followed by reperfusion. The study animals received 4 g Mg intravenously starting at 15 min of occlusion (5 min before reperfusion) and continuing during reperfusion.
Results are presented as percent change from baseline +/- SEM. Magnesium blunted the peak AFR increase: at 4 min of reperfusion there was a 4.7 +/- 3.3% increase in AFR signal in the dogs receiving Mg versus an 18.2 +/- 3.3% increase in the control animals (p < 0.05). Total radical flux was reduced during reperfusion by 53% in the Mg dogs compared with controls (p < 0.05).
Magnesium attenuates AFR increase after an occlusion-reperfusion sequence. To our knowledge this is the first in vivo real-time demonstration of Mg's impact on free radicals.
本研究表明，在短暂的冠状动脉闭塞-再灌注过程后，镁（Mg）可减少自由基。
镁已被证明可减小急性心肌梗死患者的梗死面积。我们推测镁的这一作用是通过其对自由基的作用实现的。
对18只杂种犬进行研究（9只作为对照，9只给予镁）。将导管插入冠状窦以持续采血。使用Varian E-4电子顺磁共振光谱仪监测冠状窦血液中的抗坏血酸自由基（AFR）信号；AFR是总氧化应激的一个指标。左前降支冠状动脉闭塞20分钟后进行再灌注。研究动物在闭塞15分钟时（再灌注前5分钟）开始静脉注射4克镁，并在再灌注期间持续给药。
结果以相对于基线的变化百分比±标准误表示。镁抑制了AFR的峰值增加：在再灌注4分钟时，接受镁的犬的AFR信号增加了4.7±3.3%，而对照动物增加了18.2±3.3%（p<0.05）。与对照组相比，镁处理组犬在再灌注期间的总自由基通量降低了53%（p<0.05）。
镁可减轻闭塞-再灌注序列后的AFR增加。据我们所知，这是首次在体内实时证明镁对自由基的影响。
