Radovits Tamás, Zotkina Julia, Lin Li-Ni, Bömicke Timo, Arif Rawa, Gerö Domokos, Horváth Eszter M, Karck Matthias, Szabó Csaba, Szabó Gábor
The Laboratory of Cardiac Surgery Department of Cardiac Surgery, University of Heidelberg, 69120 Heidelberg, Germany.
Exp Biol Med (Maywood). 2007 Oct;232(9):1204-12. doi: 10.3181/0701-RM-16.
Reactive oxygen species, such as myeloperoxidase-derived hypochlorite, induce oxidative stress and DNA injury. The subsequent activation of the DNA-damage-poly(ADP-ribose) polymerase (PARP) pathway has been implicated in the pathogenesis of various diseases, including ischemia-reperfusion injury, circulatory shock, diabetic complications, and atherosclerosis. We investigated the effect of PARP inhibition on the impaired endothelium-dependent vasorelaxation induced by hypochlorite. In organ bath experiments for isometric tension, we investigated the endothelium-dependent and endothelium-independent vasorelaxation of isolated rat aortic rings using cumulative concentrations of acetylcholine and sodium nitro-prusside. Endothelial dysfunction was induced by exposing rings to hypochlorite (100-400 microM). In the treatment group, rings were preincubated with the PARP inhibitor INO-1001. DNA strand breaks were assessed by the TUNEL method. Immunohistochemistry was performed for 4-hydroxynonenal (a marker of lipid peroxidation), nitrotyrosine (a marker of nitrosative stress), and poly(ADP-ribose) (an enzymatic product of PARP). Exposure to hypochlorite resulted in a dose-dependent impairment of endothelium-dependent vasorelaxation of aortic rings, which was significantly improved by PARP inhibition, whereas the endothelium-independent vasorelaxation remained unaffected. In the hypochlorite groups we found increased DNA breakage, lipidperoxidation, and enhanced nitrotyrosine formation. The hypochloride-induced activation of PARP was prevented by INO-1001. Our results demonstrate that PARP activation contributes to the pathogenesis of hypochlorite-induced endothelial dysfunction, which can be prevented by PARP inhibitors.
活性氧物质，如髓过氧化物酶衍生的次氯酸盐，可诱导氧化应激和DNA损伤。DNA损伤-多聚（ADP-核糖）聚合酶（PARP）途径的后续激活与包括缺血再灌注损伤、循环性休克、糖尿病并发症和动脉粥样硬化在内的各种疾病的发病机制有关。我们研究了PARP抑制对次氯酸盐诱导的内皮依赖性血管舒张功能受损的影响。在等长张力的器官浴实验中，我们使用累积浓度的乙酰胆碱和硝普钠研究了离体大鼠主动脉环的内皮依赖性和非内皮依赖性血管舒张。通过将血管环暴露于次氯酸盐（100 - 400 microM）来诱导内皮功能障碍。在治疗组中，血管环预先与PARP抑制剂INO-1001孵育。通过TUNEL法评估DNA链断裂。对4-羟基壬烯醛（脂质过氧化的标志物）、硝基酪氨酸（亚硝化应激的标志物）和多聚（ADP-核糖）（PARP的酶促产物）进行免疫组织化学检测。暴露于次氯酸盐导致主动脉环内皮依赖性血管舒张功能呈剂量依赖性受损，PARP抑制可显著改善这种情况，而非内皮依赖性血管舒张则不受影响。在次氯酸盐组中，我们发现DNA断裂增加、脂质过氧化增加以及硝基酪氨酸形成增强。INO-1001可防止次氯酸盐诱导的PARP激活。我们的结果表明，PARP激活促成了次氯酸盐诱导的内皮功能障碍的发病机制，PARP抑制剂可预防这种情况。
