Kline Erik R, Bassit Leda, Hernandez-Santiago Brenda I, Detorio Mervi A, Liang Bill, Kleinhenz Dean J, Walp Erik R, Dikalov Sergey, Jones Dean P, Schinazi Raymond F, Sutliff Roy L
Division of Pulmonary, Allergy and Critical Care Medicine, Emory University School of Medicine/Atlanta VA Medical Center, Atlanta, GA 30033, USA.
Cardiovasc Toxicol. 2009 Mar;9(1):1-12. doi: 10.1007/s12012-008-9029-8. Epub 2008 Dec 9.
Nucleoside reverse transcriptase inhibitors (NRTIs), such as zidovudine (AZT) and stavudine (d4T), cause toxicities to numerous tissues, including the liver and vasculature. While much is known about hepatic NRTI toxicity, the mechanism of toxicity in endothelial cells is incompletely understood. Human aortic endothelial and HepG2 liver cells were exposed to 1 muM AZT or d4T for up to 5 weeks. Markers of oxidative stress, mitochondrial function, NRTI phosphorylation, mitochondrial DNA (mtDNA) levels, and cytotoxicity were monitored over time. In endothelial cells, AZT significantly oxidized glutathione redox potential, increased total cellular and mitochondrial-specific superoxide, decreased mitochondrial membrane potential, increased lactate release, and caused cell death from weeks 3 through 5. Toxicity occurred in the absence of di- and tri-phosphorylated AZT and mtDNA depletion. These data show that oxidative stress and mitochondrial dysfunction in endothelial cells occur with a physiologically relevant concentration of AZT, and require long-term exposure to develop. In contrast, d4T did not induce endothelial oxidative stress, mitochondrial dysfunction, or cytotoxicity despite the presence of d4T-triphosphate. Both drugs depleted mtDNA in HepG2 cells without causing cell death. Endothelial cells are more susceptible to AZT-induced toxicity than HepG2 cells, and AZT caused greater endothelial dysfunction than d4T because of its pro-oxidative effects.
核苷类逆转录酶抑制剂（NRTIs），如齐多夫定（AZT）和司他夫定（d4T），会对包括肝脏和脉管系统在内的多种组织产生毒性。虽然人们对肝脏NRTI毒性了解很多，但内皮细胞中毒性的机制尚不完全清楚。将人主动脉内皮细胞和HepG2肝细胞暴露于1 μM的AZT或d4T中长达5周。随着时间的推移，监测氧化应激、线粒体功能、NRTI磷酸化、线粒体DNA（mtDNA）水平和细胞毒性的标志物。在内皮细胞中，AZT显著氧化谷胱甘肽氧化还原电位，增加总细胞和线粒体特异性超氧化物，降低线粒体膜电位，增加乳酸释放，并在第3周至第5周导致细胞死亡。毒性在没有二磷酸和三磷酸AZT以及mtDNA耗竭的情况下发生。这些数据表明，内皮细胞中的氧化应激和线粒体功能障碍在生理相关浓度的AZT作用下发生，并且需要长期暴露才会出现。相比之下，尽管存在三磷酸d4T，但d4T并未诱导内皮细胞氧化应激、线粒体功能障碍或细胞毒性。两种药物都使HepG2细胞中的mtDNA耗竭，但未导致细胞死亡。内皮细胞比HepG2细胞更容易受到AZT诱导的毒性作用，并且由于其促氧化作用，AZT比d4T导致更大的内皮功能障碍。
