Fiorillo Claudia, Pace Stefania, Ponziani Vanessa, Nediani Chiara, Perna Avio Maria, Liguori Piero, Cecchi Cristina, Nassi Niccolò, Donzelli Gian Paolo, Formigli Lucia, Nassi Paolo
Dipartimento di Scienze Biochimiche, Università di Firenze, Italy.
Free Radic Res. 2002 Jan;36(1):79-87. doi: 10.1080/10715760210168.
Free radicals and other reactive species generated during reperfusion of ischemic tissues may cause DNA damage and, consequently, the activation of the nuclear enzyme poly(ADP-ribose) polymerase (PARP). An excessive PARP activation may result in a depletion of intracellular NAD+ and ATP, hence cell suffering and, ultimately, cell death. The present study is aimed at clarifying the role of PARP in a heart transplantation procedure and the contribution of myocyte necrosis and/or apoptosis to this process. In our experimental model, rat heart subjected to heterotopic transplantation, low temperature global ischemia (2 h) was followed by an in vivo reperfusion (30 or 60 min). Under these conditions clear signs of oxidative stress, such as lipoperoxidation and DNA strand breaks, were evident. In addition to a marked activation, accompanied by a significant NAD+ and ATP depletion, PARP protein levels significantly increased after 60 min of reperfusion. Ultrastructural analysis showed nuclear clearings, intracellular oedema and plasma membrane discontinuity. Other relevant observations were the absence of typical signs of apoptosis like caspase-3 activation and PARP cleavage, random DNA fragmentation, rise in serum levels of heart damage markers. Our results suggest that during heart transplantation, the activation of PARP, causing energy depletion, results in myocardial cell injury whose dominant feature, at least in our experimental model, is necrosis rather than apoptosis.
缺血组织再灌注过程中产生的自由基和其他活性物质可能会导致DNA损伤，进而激活核酶聚（ADP - 核糖）聚合酶（PARP）。PARP过度激活可能导致细胞内NAD⁺和ATP耗竭，从而使细胞受损，最终导致细胞死亡。本研究旨在阐明PARP在心脏移植过程中的作用以及心肌细胞坏死和/或凋亡对这一过程的影响。在我们的实验模型中，对大鼠心脏进行异位移植，先进行2小时的低温全心缺血，然后进行体内再灌注（30或60分钟）。在这些条件下，明显出现了氧化应激的迹象，如脂质过氧化和DNA链断裂。除了显著激活外，同时伴有明显的NAD⁺和ATP耗竭，再灌注60分钟后PARP蛋白水平显著升高。超微结构分析显示核空泡化、细胞内水肿和质膜连续性中断。其他相关观察结果包括未出现典型的凋亡迹象，如半胱天冬酶 - 3激活和PARP裂解、随机DNA片段化以及心脏损伤标志物血清水平升高。我们的结果表明，在心脏移植过程中，PARP的激活导致能量耗竭，从而引起心肌细胞损伤，至少在我们的实验模型中，其主要特征是坏死而非凋亡。
