Moroni F, Meli E, Peruginelli F, Chiarugi A, Cozzi A, Picca R, Romagnoli P, Pellicciari R, Pellegrini-Giampietro D E
Dipartimento di Farmacologia Preclinica e Clinica, Università di Firenze, Viale G. Pieraccini 6, I-50139 Florence, Italy.
Cell Death Differ. 2001 Sep;8(9):921-32. doi: 10.1038/sj.cdd.4400884.
An excessive activation of poly(ADP-ribose) polymerase (PARP) has been proposed to play a key role in post-ischemic neuronal death. We examined the neuroprotective effects of the PARP inhibitors benzamide, 6(5H)-phenanthridinone, and 3,4-dihydro-5-[4-1(1-piperidinyl)buthoxy]-1(2H)-isoquinolinone in three rodent models of cerebral ischemia. Increasing concentrations of the three PARP inhibitors attenuated neuronal injury induced by 60 min oxygen-glucose deprivation (OGD) in mixed cortical cell cultures, but were unable to reduce CA1 pyramidal cell loss in organotypic hippocampal slices exposed to 30 min OGD or in gerbils following 5 min bilateral carotid occlusion. We then examined the necrotic and apoptotic features of OGD-induced neurodegeneration in cortical cells and hippocampal slices using biochemical and morphological approaches. Cortical cells exposed to OGD released lactate dehydrogenase into the medium and displayed ultrastructural features of necrotic cell death, whereas no caspase-3 activation nor morphological characteristics of apoptosis were observed at any time point after OGD. In contrast, a marked increase in caspase-3 activity was observed in organotypic hippocampal slices after OGD, together with fluorescence and electron microscope evidence of apoptotic neuronal death in the CA1 subregion. Moreover, the caspase inhibitor Z-VAD-FMK reduced OGD-induced CA1 pyramidal cell loss. These findings suggest that PARP overactivation may be an important mechanism leading to post-ischemic neurodegeneration of the necrotic but not of the apoptotic type.
聚（ADP - 核糖）聚合酶（PARP）的过度激活被认为在缺血后神经元死亡中起关键作用。我们在三种啮齿动物脑缺血模型中研究了PARP抑制剂苯甲酰胺、6（5H）-菲啶酮和3,4 - 二氢 - 5 - [4 - 1（1 - 哌啶基）丁氧基] - 1（2H）-异喹啉酮的神经保护作用。在混合皮质细胞培养物中，三种PARP抑制剂浓度的增加减轻了60分钟氧 - 葡萄糖剥夺（OGD）诱导的神经元损伤，但在暴露于30分钟OGD的器官型海马切片或5分钟双侧颈动脉闭塞后的沙鼠中，它们无法减少CA1锥体细胞的损失。然后，我们使用生化和形态学方法研究了OGD诱导的皮质细胞和海马切片神经退行性变的坏死和凋亡特征。暴露于OGD的皮质细胞将乳酸脱氢酶释放到培养基中，并表现出坏死性细胞死亡的超微结构特征，而在OGD后的任何时间点均未观察到caspase - 3激活或凋亡的形态学特征。相比之下，OGD后在器官型海马切片中观察到caspase - 3活性显著增加，同时有荧光和电子显微镜证据表明CA1亚区域存在凋亡性神经元死亡。此外，caspase抑制剂Z - VAD - FMK减少了OGD诱导的CA1锥体细胞损失。这些发现表明，PARP过度激活可能是导致缺血后坏死型而非凋亡型神经退行性变的重要机制。
