Maulik N, Sasaki H, Addya S, Das D K
Department of Surgery, University of Connecticut School of Medicine, Farmington, 06030-1110, USA.
FEBS Lett. 2000 Nov 17;485(1):7-12. doi: 10.1016/s0014-5793(00)02174-8.
Reperfusion of ischemic myocardium results in apoptotic cell death and DNA fragmentation. Several transcription factors are known to regulate the apoptotic cell death. This study sought to examine the regulation of cardiomyocyte apoptosis by these transcription factors. Isolated working rat hearts were divided into six groups: control, 15 min ischemia, 60 min ischemia, 15 min ischemia followed by 2 h reperfusion, ischemic stress adaptation by subjecting the hearts to four cyclic episodes to 5 min ischemia, each followed by 10 min of reperfusion, and adaptation followed by 15 min ischemia and 2 h reperfusion. Redox-regulated transcription factors, NF kappa B and AP-1 and the expression of two anti- and pro-apoptotic genes, Bcl-2 and p53 were determined. The results demonstrated NF kappa B and AP-1 progressively and steadily increased as a function of the duration of ischemia. In the adapted heart, NF kappa B binding remained high while AP-1 binding was lowered to almost baseline value. The anti-oxidant gene, Bcl-2 was downregulated in the ischemic/reperfused heart, but upregulated in the preconditioned myocardium. Significant induction of the expression of p53 occurred after ischemia and reperfusion. Apoptotic cells were barely detected in the adapted myocardium which was subjected to the same ischemia/reperfusion protocol. The results demonstrate for the first time differential regulation of cardiomyocyte apoptosis by pro- and anti-apoptotic transcription factors and genes as a function of different durations of ischemia and reperfusion.
缺血心肌的再灌注会导致凋亡性细胞死亡和DNA片段化。已知几种转录因子可调节凋亡性细胞死亡。本研究旨在探讨这些转录因子对心肌细胞凋亡的调节作用。将离体工作大鼠心脏分为六组：对照组、15分钟缺血组、60分钟缺血组、15分钟缺血后再灌注2小时组、通过使心脏经历四个5分钟缺血循环（每次缺血后再灌注10分钟）进行缺血应激适应组，以及适应后再进行15分钟缺血和2小时再灌注组。测定了氧化还原调节的转录因子NF-κB和AP-1以及两个抗凋亡和促凋亡基因Bcl-2和p53的表达。结果表明，NF-κB和AP-1随着缺血持续时间的延长而逐渐稳定增加。在适应的心脏中，NF-κB结合仍然很高，而AP-1结合降低到几乎基线值。抗氧化基因Bcl-2在缺血/再灌注心脏中下调，但在预处理心肌中上调。缺血和再灌注后p53表达显著诱导。在经历相同缺血/再灌注方案的适应心肌中几乎未检测到凋亡细胞。结果首次证明促凋亡和抗凋亡转录因子及基因对心肌细胞凋亡的调节因缺血和再灌注持续时间的不同而存在差异。
