Day B J, Shawen S, Liochev S I, Crapo J D
Department of Medicine, Duke University Medical Center, Durham, North Carolina, USA.
J Pharmacol Exp Ther. 1995 Dec;275(3):1227-32.
There is an increased interest in development of therapeutic agents to treat disease states that involve reactive oxygen species in their pathophysiology. The metalloporphyrins, MnTBAP and ZnTBAP, were found to be active in a superoxide dismutase (SOD) assay. The efficacy of these compounds were tested against a well established model of intracellular superoxide-mediated cell injury. Paraquat generates superoxide by redox cycling with intracellular diaphorases and molecular oxygen. SOD mimetics were employed in a cell culture model with calf pulmonary artery endothelial cells (CPA-47) grown to near confluence in 24-well plates. Cell injury was assessed by measuring the release of cytosolic lactate dehydrogenase into the cell medium and by the number of adherent cells remaining after treatment. Exposure to various concentrations of paraquat for 4 h produced a dose-dependent injury response that was attenuated by 50 microM SOD mimetic, MnTBAP. MnTBAP also protected endothelial cells in a dose-dependent manner (EC50 approximately 40 microM) against paraquat (2 mM), whereas its less active analog (ZnTBAP) did not protect them. The protective effect of MnTBAP appears to be due to its intracellular superoxide-scavenging activity because neither the zinc form or exogenous CuZnSOD protected the cells against paraquat-induced injury. These studies suggest that metalloporphyrin-based SOD mimetics may be useful agents in preventing injury and disease states associated with the generation of intracellular reactive oxygen species.
对于开发治疗那些在病理生理学中涉及活性氧的疾病状态的治疗药物，人们的兴趣日益浓厚。金属卟啉MnTBAP和ZnTBAP在超氧化物歧化酶（SOD）测定中表现出活性。这些化合物的疗效在一个成熟的细胞内超氧化物介导的细胞损伤模型中进行了测试。百草枯通过与细胞内的黄递酶和分子氧进行氧化还原循环产生超氧化物。超氧化物歧化酶模拟物被用于一个细胞培养模型，其中小牛肺动脉内皮细胞（CPA - 47）在24孔板中生长至接近汇合状态。通过测量细胞溶质乳酸脱氢酶释放到细胞培养基中的量以及处理后剩余的贴壁细胞数量来评估细胞损伤。暴露于各种浓度的百草枯4小时会产生剂量依赖性的损伤反应，50微摩尔的超氧化物歧化酶模拟物MnTBAP可减轻这种反应。MnTBAP还以剂量依赖性方式（EC50约为40微摩尔）保护内皮细胞免受百草枯（2毫摩尔）的损伤，而其活性较低的类似物（ZnTBAP）则不能保护它们。MnTBAP的保护作用似乎归因于其细胞内超氧化物清除活性，因为锌形式或外源性铜锌超氧化物歧化酶都不能保护细胞免受百草枯诱导的损伤。这些研究表明，基于金属卟啉的超氧化物歧化酶模拟物可能是预防与细胞内活性氧生成相关的损伤和疾病状态的有用药物。
