Hasinoff Brian B, Schnabl Kareena L, Marusak Rosemary A, Patel Daywin, Huebner Erwin
Faculty of Pharmacy, University of Manitoba, Winnipeg, Manitoba, Canada R3T 2N2.
Cardiovasc Toxicol. 2003;3(2):89-99. doi: 10.1385/ct:3:2:89.
The clinically approved antioxidant cardioprotective agent dexrazoxane (ICRF-187) was examined for its ability to protect neonatal rat cardiac myocytes from doxorubicin-induced damage. Doxorubicin is thought to induce oxidative stress on the heart muscle, both through reductive activation to its semiquinone form, and by the production of hydroxyl radicals mediated by its complex with iron. Hydrolyzed dexrazoxane metabolites prevent site-specific iron-based oxygen radical damage by displacing iron from doxorubicin and chelating free and loosely bound iron. The mitochondrial stain MitoTracker Green FM and doxorubicin were shown by epifluorescence microscopy to accumulate in the myocyte mitochondria. An epifluorescence microscopic image analysis method to measure mitochondrial damage was developed using the mitochondrial membrane potential sensing ratiometric dye JC-1. This method was used to show that dexrazoxane protected against doxorubicin-induced depolarization of the myocyte mitochondrial membrane. Dexrazoxane also attenuated doxorubicin-induced oxidation of intracellular dichlorofluorescin. Annexin V-FITC/propidium iodide staining of myocytes was used to demonstrate that, depending on the concentration, doxorubicin caused both apoptotic and necrotic damage. These results suggest that doxorubicin may be cardiotoxic by damaging the mitochondria and dexrazoxane may be protective by preventing iron-based oxidative damage.
对临床批准的抗氧化心脏保护剂右丙亚胺（ICRF-187）保护新生大鼠心肌细胞免受阿霉素诱导损伤的能力进行了研究。阿霉素被认为会通过还原激活为其半醌形式以及通过与铁形成复合物介导产生羟基自由基，从而对心肌诱导氧化应激。水解的右丙亚胺代谢产物通过将铁从阿霉素中置换出来并螯合游离和松散结合的铁，防止位点特异性的基于铁的氧自由基损伤。通过落射荧光显微镜观察发现，线粒体染色剂MitoTracker Green FM和阿霉素会在心肌细胞线粒体中积累。利用线粒体膜电位传感比率染料JC-1开发了一种落射荧光显微镜图像分析方法来测量线粒体损伤。该方法用于表明右丙亚胺可防止阿霉素诱导的心肌细胞线粒体膜去极化。右丙亚胺还减弱了阿霉素诱导的细胞内二氯荧光素氧化。利用膜联蛋白V-异硫氰酸荧光素/碘化丙啶对心肌细胞进行染色，以证明根据浓度不同，阿霉素会导致凋亡性损伤和坏死性损伤。这些结果表明，阿霉素可能通过损伤线粒体而具有心脏毒性，而右丙亚胺可能通过防止基于铁的氧化损伤而具有保护作用。
