Cellular thiols redox status:: a switch for NF-κB activation during myocardial post-ischaemic reperfusion

A. CARGNONI, C. CECONI, G. GAIA, L. AGNOLETTI AND R. FERRARI. Cellular Thiols Redox Status: a Switch for NF-kappaB Activation During Myocardial Post-ischaemic Reperfusion. Journal of Molecular and Cellular Cardiology (2002) 34, 997-1005. Myocardial ischaemia/reperfusion induces NF-kappaB activation, but little is known about the stimuli through which it occurs. Aims of the study were to investigate whether: (a) oxidative stress induced by ischaemia/reperfusion is linked with NF-kappaB activation; (b) counteraction of oxidative stress by N-acetyl cysteine (NAC) reduces NF-kappaB activation. At this purpose, in isolated rat hearts, we induced mild (15 min) and severe (3 0 min) ischaemia; a group of the hearts submitted to severe ischaemia were treated with NAC. Our data indicate that reperfusion after severe ischaemia activates NF-kappaB: the presence of p65 in the nuclear extracts was 274.5 +/- 18.6% vs aerobia; (P < 0.05) and an induced DNA-binding activity was detected. NF-kappaB translocation occurs in parallel with myocardial decrease in reduced glutathione and protein -SH (from 9.2 +/- 0.4 to 5.4 +/- 0.3 nmol/mg prot, P < 0.01, and from 350.3 +/- 16.6 to 296.0 +/- 9.1 nmol/mg prot, P < 0.05) and accumulation of oxidised glutathione-GSSG-(from 0.075 +/- 0.005 to 0.118 +/- 0.007 nmol/mg prot, P < 0.01). When ischaemia/reperfusion does not result in any oxidative stress (in mild ischaemia or severe ischaemia plus NAC), NF-kappaB does not translocate. A significant correlation was found between the activation of NF-kappaB and the accumulation of GSSG in the myocardium. Our data indicate that an oxidative shift of cellular thiolic pools can modulate the genic transcription of the heart through NF-kappaB activation. (C) 2002 Elsevier Science Ltd. All rights reserved.