Antioxidative properties of pyruvate and protection of the ischemic rat heart during cardioplegia
Antioxidative properties of pyruvate and protection of the ischemic rat heart during cardioplegia
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DOI：
10.1097/00005344-199911000-00005
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发表时间：
1999-11-01
影响因子：
3
通讯作者：
Rochette, L
中科院分区：
文献类型：
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作者：
Dobsak, P;Courderot-Masuyer, C;Rochette, L
心脏移植过程中氧自由基的形成似乎与缺血和再灌注过程中发生的变化有关，并且可以解释供体心脏保存时间短的原因。我们研究的目的是（a）分析丙酮酸在冷心麻痹和缺血/再灌注过程中的保护作用，以及（b）在体外研究该化合物的自由基清除特性。灌注30分钟后，用心脏停搏液逮捕离体的工作大鼠心脏，在4℃下在B21溶液中保存4小时，并用Krebs-Henseleit缓冲液再灌注45分钟。将丙酮酸 (2 mM) 添加到 Krebs-Henseleit、心脏停搏液和储存溶液中，并在整个实验过程中记录功能参数。在第二部分中，将对照心脏和用丙酮酸处理的心脏通过主动脉插管，并通过Langendorff方法灌注30分钟，用心停跳液停顿，在4℃下在B21溶液中储存4小时，并通过Langendorff方法再灌注45分钟。测定心脏匀浆中的丙二醛和α-生育酚水平。在缺血/再灌注序列结束时，还对组织样本（左心室）进行了凋亡细胞的原位检测。为了证明丙酮酸的体外抗氧化作用，我们通过电子顺磁共振 (EPR) 光谱监测了 (a) 其羟自由基清除特性，以及 (b) 在芬顿系统 (H2O2/Cu2+) 存在下，别藻蓝蛋白的荧光减弱。缺血4小时，然后心肌再灌注，导致机械功能大幅下降。遭受这种缺血并用丙酮酸预处理的心脏显示出功能恢复的显着改善。缺血/再灌注方案后，用丙酮酸处理的心脏中丙二醛水平没有显着降低。然而，与对照组相比，丙酮酸组的α-生育酚水平较高。再灌注期结束时，与对照心脏相比，用丙酮酸处理的心脏中的凋亡细胞水平显着降低。 EPR 研究表明丙酮酸是一种有效的羟基清除剂，中位抑制浓度 (IC50) 为 8 mM。别藻蓝蛋白测定还显示丙酮酸对羟基自由基的剂量依赖性作用。总之，这些发现表明丙酮酸可以防止离体心脏的再灌注损伤，这可能是由于其抗氧化特性。丙酮酸的应用可能有助于保存器官移植用的心脏。
Formation of oxygen free radicals during heart transplantation seems to be related to the alterations occurring during ischemia and reperfusion and could explain the short preservation time of donor hearts. The aim of our study was (a) to analyze the protective effects of pyruvate during cold cardioplegia and ischemia/reperfusion sequence, and (b) to investigate in vitro the radical scavenging properties of this compound. After 30 min of perfusion, isolated working rat hearts were arrested by cardioplegic solution, stored 4 h in B21 solutions at 4 degrees C, and reperfused with Krebs-Henseleit buffer for 45 min. Pyruvate (2 mM) was added to Krebs-Henseleit, cardioplegic, and storage solutions, and functional parameters were recorded throughout the experiments. In a second part, control hearts and hearts treated with pyruvate were cannulated via the aorta and perfused for 30 min by the Langendorff method, arrested by cardioplegic solution, stored 4 h in B21 solutions at 4 degrees C, and reperfused for 45 min by the Langendorff method. Malonedialdehyde and alpha-tocopherol levels were determined on heart homogenate. In situ detection of apoptotic cells also was performed on tissue samples (left ventricle) at the end of the ischemia/reperfusion sequence. To demonstrate in vitro the antioxidant effects of pyruvate, we monitored (a) its hydroxyl radical scavenging properties by using electron para-magnetic resonance (EPR) spectroscopy, and (b) the decrease of fluorescence of allophycocyanin, in the presence of a Fenton system (H2O2/Cu2+). Ischemia for 4 h, followed by myocardial reperfusion, resulted in substantially reduced mechanical function. Hearts subjected to this ischemia and pretreated with pyruvate showed a significant improvement in the function recovery. After the ischemia/reperfusion protocol, no significant decrease of malonedialdehyde levels was shown on hearts treated with pyruvate. However, alpha-tocopherol levels were higher in the pyruvate group compared with the control group. At the end of the reperfusion period, levels of apoptotic cells were significantly lower in hearts treated with pyruvate compared with control hearts. EPR studies showed that pyruvate was an efficient hydroxyl scavenger, with a median inhibitory concentration (IC50) of 8 mM. The allophycocyanin assay also showed a dose-dependent effect of pyruvate against hydroxyl radicals. In conclusion, these findings showed that pyruvate could prevent reperfusion injuries in the isolated heart, probably by its antioxidative properties. The application of pyruvate may contribute to the preservation of hearts for organ transplantation.