Vrbjar N, Zöllner S, Haseloff R F, Pissarek M, Blasig I E
Institute for Heart Research, Slovak Acadamy of Sciences, Bratislava, Slovak Republic.
Mol Cell Biochem. 1998 Sep;186(1-2):107-15.
Post-ischemic reperfusion causes cardiac dysfunction and radical-induced lipid peroxidation (LPO) detectable by ESR spin trapping. This study deals with the applicability of the spin trapping technique to pharmacological investigations during myocardial reperfusion injury. The use of the spin trap phenylbutylnitrone (PBN, 3 mM) in isolated rat hearts demonstrated the release of alkoxyl radicals (aN = 1.39 mT, aHbeta = 0.19 mT) formed particularly within the first 15 min of reperfusion following 30 min of ischemia. The decline of radicals, after 10 min of reperfusion, was accompanied by recovery of function in 80% of the hearts. The radical concentration in the coronary effluent (maximum after 7.5 min) was reduced by the infusion of 1 mM mercaptopropionylglycine (MPG, 2.7+/-0.5 U/ml, p < 0.001) or 5 microM vitamin E (11.7+/-0.8 U/ml, p < 0.001), compared to the (PBN-containing) control (29.7+/-4.3 U/ml). Moreover, functional recovery (left ventricular developed pressure, LVDP 91.6 +/-20% of pre-ischemic level, p < 0.05) was improved by the hydrophilic radical scavenger MPG, compared to the (PBN-containing) control (LVDP 50.5+/-15.7% of baseline). PBN alone led to higher functional recovery (p < 0.05) and reduced VF (duration of ventricular fibrillation; 7.10+/-0.36 min/30 min, p < 0.05), compared to the untreated (PBN-free) control (LVDP 26.6+/-11.8%; VF 19.42+/-3.64 min/30 min). The Ca antagonist verapamil (0.1 microM), MPG, and the lipophilic vitamin E showed cardioprotection in the absence of PBN: post-ischemic recovery of LVDP was 25.4+/-6.8% (p < 0.05), 39.6+/-12.7% (p < 0.05) and 52.4+/-2.6% (p < 0.01), respectively, compared to the corresponding untreated control (13.3+/-6.6%). Whereas verapamil and vitamin E were able to protect the heart when present alone, they offered no additive effect in the presence of PBN. Therefore, PBN can be used to estimate the radical scavenger properties of an agent in the heart. However, because of the protective properties of PBN itself, the results of simultaneous investigations of the effects of other compounds, such as Ca antagonists or lipophilic radical scavengers, on heart function may be limited.
缺血后再灌注会导致心脏功能障碍以及通过电子自旋共振（ESR）自旋捕获可检测到的自由基诱导的脂质过氧化（LPO）。本研究探讨了自旋捕获技术在心肌再灌注损伤药理学研究中的适用性。在离体大鼠心脏中使用自旋捕获剂苯基丁基硝酮（PBN，3 mM），结果表明在30分钟缺血后再灌注的最初15分钟内，特别是形成了烷氧基自由基（aN = 1.39 mT，aHβ = 0.19 mT）。再灌注10分钟后自由基减少，同时80%的心脏功能得到恢复。与（含PBN的）对照组（29.7±4.3 U/ml）相比，输注1 mM巯基丙酰甘氨酸（MPG，2.7±0.5 U/ml，p < 0.001）或5 μM维生素E（11.7±0.8 U/ml，p < 0.001）可降低冠状动脉流出液中的自由基浓度（7.5分钟时达到最高）。此外，与（含PBN的）对照组（左心室舒张末压，LVDP为基线的50.5±15.7%）相比，亲水性自由基清除剂MPG可改善功能恢复（左心室舒张末压，LVDP为缺血前水平的91.6±20%，p < 0.05）。与未处理的（不含PBN的）对照组（LVDP为26.6±11.8%；室颤持续时间为19.42±3.64分钟/30分钟）相比，单独使用PBN可导致更高的功能恢复（p < 0.05）并减少室颤（室颤持续时间；7.10±0.36分钟/30分钟，p < 0.05）。钙拮抗剂维拉帕米（0.1 μM）、MPG和亲脂性维生素E在不存在PBN的情况下显示出心脏保护作用：与相应的未处理对照组（13.3±6.6%）相比，缺血后LVDP的恢复分别为25.4±6.8%（p < 0.05）、39.6±12.7%（p < 0.05）和52.4±2.6%（p < 0.01）。虽然维拉帕米和维生素E单独存在时能够保护心脏，但在存在PBN的情况下它们没有相加作用。因此，PBN可用于评估一种药物在心脏中的自由基清除特性。然而，由于PBN本身的保护特性，同时研究其他化合物（如钙拮抗剂或亲脂性自由基清除剂）对心脏功能的影响结果可能会受到限制。
