Bowes J, McDonald M C, Piper J, Thiemermann C
William Harvey Research Institute, St Bartholomew's, London, UK.
Cardiovasc Res. 1999 Jan;41(1):126-34. doi: 10.1016/s0008-6363(98)00221-1.
Inhibitors of poly (ADP-ribose) synthetase (PARS) activity reduce the infarct size caused by regional myocardial ischaemia and reperfusion in the rabbit and rat in vivo. The mechanism of action of these inhibitors is unclear. Here we investigate the effects of the PARS inhibitor 3-aminobenzamide (3-AB) on infarct size caused by ischaemia and reperfusion of the isolated, perfused heart of the rat. We also investigate the role of PARS in the hydrogen peroxide-mediated cell injury/necrosis in rat cardiac myoblasts.
Rat isolated hearts perfused at constant pressure (80 mmHg) were subjected to 35 min of regional ischaemia and 2 h of reperfusion. Infarct size was determined at the end of the experiment using nitro-blue tetrazolium. 3-AB (300 microM) or 3-aminobenzoic acid (3-ABA, 300 microM) were infused during the reperfusion period. Rat cardiac myoblasts (H9c2 cells) were preincubated with the PARS inhibitors, 3-AB. nicotinamide (Nic) or 1,5-dihydroxyisoquinoline (ISO) or the inactive analogues 3-ABA or nicotinic acid (NicA) prior to exposure with hydrogen peroxide (1 mM). Cell injury was assessed by measuring mitochondrial respiration and cell necrosis by measuring the release of LDH. PARS activity was determined by measuring the incorporation of NAD into nuclear proteins.
Regional ischaemia and reperfusion of the isolated rat heart resulted in an infarct size of 54% which was reduced by 3-AB, but not by 3-ABA. Exposure of rat cardiac myoblasts to hydrogen peroxide caused an increase in PARS activity and cell injury/necrosis which was attenuated by pretreatment with the PARS inhibitors.
Inhibition of the activity of PARS attenuates the cell death associated with oxidant stress in rat cardiac myoblasts and heart.
聚（ADP - 核糖）合成酶（PARS）活性抑制剂可减小家兔和大鼠体内局部心肌缺血再灌注所致的梗死面积。这些抑制剂的作用机制尚不清楚。在此，我们研究PARS抑制剂3 - 氨基苯甲酰胺（3 - AB）对大鼠离体灌注心脏缺血再灌注所致梗死面积的影响。我们还研究了PARS在过氧化氢介导的大鼠心肌成纤维细胞损伤/坏死中的作用。
对在恒压（80 mmHg）下灌注的大鼠离体心脏进行35分钟的局部缺血和2小时的再灌注。实验结束时用硝基蓝四氮唑测定梗死面积。在再灌注期间输注3 - AB（300 μM）或3 - 氨基苯甲酸（3 - ABA，300 μM）。大鼠心肌成纤维细胞（H9c2细胞）在暴露于过氧化氢（1 mM）之前，先用PARS抑制剂3 - AB、烟酰胺（Nic）或1,5 - 二羟基异喹啉（ISO）或无活性类似物3 - ABA或烟酸（NicA）进行预孵育。通过测量线粒体呼吸评估细胞损伤，通过测量乳酸脱氢酶释放评估细胞坏死。通过测量NAD掺入核蛋白来测定PARS活性。
大鼠离体心脏的局部缺血再灌注导致梗死面积为54%，3 - AB可减小该面积，但3 - ABA无此作用。大鼠心肌成纤维细胞暴露于过氧化氢会导致PARS活性增加以及细胞损伤/坏死增加，而PARS抑制剂预处理可减弱这种情况。
抑制PARS活性可减轻大鼠心肌成纤维细胞和心脏中与氧化应激相关的细胞死亡。
