Dulchavsky S A, Davidson S B, Cullen W J, Devasagayam T P, Diebel L N, Dutta S
Department of Surgery, Harper Hospital, Detroit, Michigan 48201, USA.
Basic Res Cardiol. 1996 Nov-Dec;91(6):418-24. doi: 10.1007/BF00788722.
During myocardial reperfusion injury, iron has been implicated in the Fenton based generation of hydroxyl radical, .OH, leading to further organ injury. Although previous studies have investigated the protective effect of iron chelators including deferoxamine (DFX) in myocardial reperfusion injury, there is little information regarding the role of iron chelation during oxidative stress produced by H2O2 on the heart. Isolated hearts from male Sprague-Dawley rats were retrograde-perfused with Krebs-Henseleit solution at 5 ml/min. After a 60-min equilibration, oxyradical challenge was instituted by the addition of H2O2 (200-600 microM) to the perfusate for 60 min. A subgroup of animals received DFX (400 microM) in the perfusate prior to challenge with 400 microM H2O2. Contractility was continuously monitored; perfusate samples for glutathione (GSH) and lactate dehydrogenase (LDH) estimations were collected at 30-min intervals. Headspace ethane, an indicator of lipid peroxidation, was estimated at 30-min intervals by gas chromatography. Control hearts maintained contractility during the perfusion period. H2O2 perfusion caused a dose dependent decrease in myocardial contractility; DFX pretreatment was partially protective. Headspace ethane slowly accumulated in control hearts; perfusion with H2O2 caused dose dependent increase in ethane accumulation indicative of enhanced lipid peroxidation. GSH and LDH in the perfusate remained low in control hearts. In contrast, H2O2 treated hearts had a dose dependent increase in the efflux of GSH and LDH which was markedly increased by perfusion with 600 microM H2O2. Pretreatment with DFX did not significantly reduce GSH or LDH efflux from hearts perfused with peroxide. While H2O2 perfusion causes a dose dependent decrease in myocardial contractility with a corresponding increase in headspace ethane release with GSH & LDH efflux indicative of oxidative stress, concurrent treatment with DFX reduces myocardial dysfunction and ethane generation. However, sublethal damage of plasma membrane still continues as reflected by continuous enhancement of LDH efflux, possibly indicating involvement of other reactive species besides hydroxyl radical.
在心肌再灌注损伤过程中，铁参与了基于芬顿反应生成羟自由基（·OH）的过程，进而导致器官进一步损伤。尽管先前的研究已经探讨了包括去铁胺（DFX）在内的铁螯合剂在心肌再灌注损伤中的保护作用，但关于铁螯合在H2O2对心脏产生的氧化应激过程中的作用，相关信息却很少。从雄性Sprague-Dawley大鼠分离出的心脏，以5毫升/分钟的速度用Krebs-Henseleit溶液进行逆行灌注。在平衡60分钟后，通过向灌注液中添加H2O2（200 - 600微摩尔）60分钟来引发氧自由基攻击。一组动物在接受400微摩尔H2O2攻击之前，先在灌注液中加入DFX（400微摩尔）。持续监测心脏收缩力；每隔30分钟收集灌注液样本以测定谷胱甘肽（GSH）和乳酸脱氢酶（LDH）。通过气相色谱法每隔30分钟测定顶空气乙烷，它是脂质过氧化的一个指标。对照心脏在灌注期间保持收缩力。H2O2灌注导致心肌收缩力呈剂量依赖性下降；DFX预处理具有部分保护作用。对照心脏中顶空气乙烷缓慢积累；用H2O2灌注导致乙烷积累呈剂量依赖性增加，表明脂质过氧化增强。对照心脏灌注液中的GSH和LDH保持在低水平。相比之下，经H2O2处理的心脏中GSH和LDH的流出呈剂量依赖性增加，在用600微摩尔H2O2灌注时显著增加。用DFX预处理并没有显著降低用过氧化物灌注的心脏中GSH或LDH的流出。虽然H2O2灌注导致心肌收缩力呈剂量依赖性下降，同时顶空气乙烷释放增加，且GSH和LDH流出表明存在氧化应激，但同时使用DFX可减轻心肌功能障碍和乙烷生成。然而，如LDH流出持续增加所反映的，质膜的亚致死性损伤仍在继续，这可能表明除了羟自由基外，还有其他活性物质参与其中。
