Paky A, Michael J R, Burke-Wolin T M, Wolin M S, Gurtner G H
Department of Medicine, New York Medical College, Valhalla 10595.
J Appl Physiol (1985). 1993 Jun;74(6):2868-74. doi: 10.1152/jappl.1993.74.6.2868.
We find spontaneous light emission from isolated Krebs-Henseleit-perfused rabbit lungs when the light-emitting super-oxide trap lucigenin is added to the perfusate. Lucigenin light emission appears to be specific for superoxide anion, because light emission from the lung caused by a superoxide-generating system is abolished by superoxide dismutase but not by catalase or dimethylthiourea. We also studied the relative sensitivity of lucigenin photoemission to superoxide and to H2O2 in vitro. Lucigenin photoemission is three to four orders of magnitude more sensitive to superoxide than to H2O2 and probably cannot detect H2O2 in concentrations thought to occur in biological systems. Basal lucigenin photoemission by the lung is oxygen dependent, because severe hypoxia completely inhibits light emission. Superoxide dismutase reduces basal photoemission by 50%, and administration of the low-molecular-weight superoxide scavenger 4,5-dihydroxy-1,3-benzene disulfonic acid (tiron) inhibits basal photoemission by approximately 90%. These observations suggest that endogenous superoxide production is primarily intracellular and that approximately half of the superoxide reaches the extracellular space. Superoxide transport may involve anion channels, because the anion channel blocker 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid increases photoemission, suggesting intracellular accumulation of superoxide. A cytochrome P-450 inhibitor, SKF 525A, or the mitochondrial transport inhibitor antimycin decreased basal photoemission by approximately 50%, suggesting that cytochrome P-450-mediated reactions and perhaps mitochondrial function contribute to basal superoxide production in the isolated perfused lung. Endogenous superoxide production may be important in regulation of pulmonary vascular reactivity and may contribute to the pathogenesis of lung reperfusion injury.
当将发光超氧化物捕获剂光泽精添加到灌注液中时，我们发现从孤立的用克氏-亨氏液灌注的兔肺中有自发的光发射。光泽精的光发射似乎对超氧阴离子具有特异性，因为由超氧化物生成系统引起的肺光发射可被超氧化物歧化酶消除，但不能被过氧化氢酶或二甲基硫脲消除。我们还在体外研究了光泽精光发射对超氧化物和过氧化氢的相对敏感性。光泽精光发射对超氧化物的敏感性比对过氧化氢高3至4个数量级，可能无法检测到生物系统中认为会出现的过氧化氢浓度。肺的基础光泽精光发射依赖于氧气，因为严重缺氧会完全抑制光发射。超氧化物歧化酶可使基础光发射降低50%，而给予低分子量超氧化物清除剂4,5-二羟基-1,3-苯二磺酸（钛铁试剂）可使基础光发射抑制约90%。这些观察结果表明内源性超氧化物的产生主要在细胞内，并且大约一半的超氧化物到达细胞外空间。超氧化物的转运可能涉及阴离子通道，因为阴离子通道阻滞剂4,4'-二异硫氰基芪-2,2'-二磺酸会增加光发射，表明超氧化物在细胞内积累。细胞色素P-450抑制剂SKF 525A或线粒体转运抑制剂抗霉素可使基础光发射降低约50%，这表明细胞色素P-450介导的反应以及可能的线粒体功能有助于离体灌注肺中基础超氧化物的产生。内源性超氧化物的产生可能在调节肺血管反应性中起重要作用，并可能导致肺再灌注损伤的发病机制。
