Haramaki N, Stewart D B, Aggarwal S, Ikeda H, Reznick A Z, Packer L
The Department of Internal Medicine III, Kurume University School of Medicine, Japan.
Free Radic Biol Med. 1998 Aug;25(3):329-39. doi: 10.1016/s0891-5849(98)00066-5.
Although cardiac endogenous antioxidants have been reported to be oxidized and decreased by ischemia-reperfusion, little is known whether the changes in these antioxidants are correlated with each other in a systematic relationship. In this study, isolated rat hearts were subjected to various periods of ischemia-reperfusion using the Langendorff method, and the content and/or redox status of tissue antioxidants were analyzed. Significant losses in the tissue hydrophilic antioxidants, ascorbate, and glutathione were observed. These losses were dependent on the duration of the reperfusion period (between 0-40 min) but not of ischemia (20-60 min). Marked increases of dehydroascorbate and glutathione disulfide, the oxidized forms of ascorbate and glutathione, respectively, were found during reperfusion, but these changes were not observed during ischemia. These findings indicate that the tissue hydrophilic antioxidants are easily oxidized and may be the first line of antioxidant defenses during reperfusion. Lipophilic antioxidants, like ubiquinol 9 and vitamin E, were not decreased during ischemia-reperfusion using regular buffer; however, if oxidative stress was induced by addition of H2O2 to the buffer solution during reperfusion after 20 min of ischemia, decreases in both the hydrophilic and hydrophobic antioxidants were noticeable. With 100 microM H2O2, the tissue antioxidant decreases were ubiquinol 9 (39%), vitamin E (3%), glutathione (44%) and ascorbate (58%). Only with 500 microM H2O2 treatment were marked decreases in tissue vitamin E (65%) observed; this was associated with almost complete depletion of tissue ubiquinol 9 (95%). These results suggest that prior to the consumption of vitamin E, other antioxidants are depleted and that vitamin E may serve as the ultimate antioxidant, protecting the integrity of cellular membranes. Thus, in this work, cardiac antioxidants were demonstrated to change in a systematically organized relationship under ischemia-reperfusion. This graded utilization of antioxidants supports the redox based antioxidant network concept, found to be present in other biological systems.
尽管有报道称心脏内源性抗氧化剂会因缺血再灌注而被氧化并减少，但对于这些抗氧化剂的变化是否以系统关系相互关联却知之甚少。在本研究中，采用Langendorff方法对离体大鼠心脏进行不同时长的缺血再灌注处理，并分析组织抗氧化剂的含量和/或氧化还原状态。观察到组织亲水性抗氧化剂、抗坏血酸和谷胱甘肽有显著损失。这些损失取决于再灌注时间（0 - 40分钟之间），而非缺血时间（20 - 60分钟）。在再灌注期间发现脱氢抗坏血酸和谷胱甘肽二硫化物（分别为抗坏血酸和谷胱甘肽的氧化形式）显著增加，但在缺血期间未观察到这些变化。这些发现表明组织亲水性抗氧化剂容易被氧化，可能是再灌注期间抗氧化防御的第一道防线。使用常规缓冲液时，亲脂性抗氧化剂如泛醇9和维生素E在缺血再灌注期间并未减少；然而，如果在缺血20分钟后的再灌注期间向缓冲溶液中添加H2O2诱导氧化应激，则亲水性和疏水性抗氧化剂都会明显减少。加入100 microM H2O2后，组织抗氧化剂的减少情况为：泛醇9（39%）、维生素E（3%）、谷胱甘肽（44%）和抗坏血酸（58%）。仅在500 microM H2O2处理时，观察到组织维生素E显著减少（65%）；这与组织泛醇9几乎完全耗尽（95%）相关。这些结果表明，在维生素E被消耗之前，其他抗氧化剂已被耗尽，并且维生素E可能作为最终的抗氧化剂，保护细胞膜的完整性。因此，在这项研究中，心脏抗氧化剂在缺血再灌注下以系统组织的关系发生变化。这种抗氧化剂的分级利用支持了基于氧化还原的抗氧化网络概念，该概念在其他生物系统中也存在。
