Shah K A, Samson S E, Grover A K
Department of Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada.
Mol Cell Biochem. 1998 Jun;183(1-2):147-52. doi: 10.1023/a:1006828205261.
Reactive oxygen species (ROS) are produced in ischemia and reperfusion. Since endothelial nitric oxide synthase (eNOS) is key to the endothelium-dependent vasodilation, we examined the effects of peroxide on this enzyme. We treated cells cultured from pig coronary artery endothelium with different concentrations of hydrogen peroxide, washed them, solubilized them and measured NOS activity by arginine to citrulline conversion. Hydrogen peroxide inhibited the eNOS activity with an IC50 value of 0.85 +/- 0.39 mM. In another experiment, we perfused arteries with solutions containing 0 or 1 mM hydrogen peroxide, washed them, removed the endothelium using a cotton swab, centrifuged and solubilized the endothelium and monitored its NOS activity. Hydrogen peroxide (1 mM) did not affect the NOS activity significantly (p > 0.05) in this assay. We conclude that the inactivation of eNOS by hydrogen peroxide does not play a major role in the ischemia-reperfusion damage because the peroxide concentrations attained during ischemia-perfusion are much lower than those affecting the eNOS activity.
活性氧（ROS）在缺血和再灌注过程中产生。由于内皮型一氧化氮合酶（eNOS）是内皮依赖性血管舒张的关键，我们研究了过氧化物对该酶的影响。我们用不同浓度的过氧化氢处理猪冠状动脉内皮细胞培养物，洗涤后使其溶解，并通过精氨酸向瓜氨酸的转化来测量一氧化氮合酶（NOS）活性。过氧化氢抑制eNOS活性，IC50值为0.85±0.39 mM。在另一项实验中，我们用含有0或1 mM过氧化氢的溶液灌注动脉，洗涤后，用棉签去除内皮，离心并溶解内皮，然后监测其NOS活性。在该测定中，1 mM过氧化氢对NOS活性没有显著影响（p>0.05）。我们得出结论，过氧化氢使eNOS失活在缺血-再灌注损伤中不发挥主要作用，因为缺血-灌注期间达到的过氧化物浓度远低于影响eNOS活性的浓度。
