Loss of myocardial protection against myocardial infarction in middle-aged transgenic mice overexpressing cardiac thioredoxin-1

// Veronica D´Annunzio 1,5,* , Virginia Perez 1,* , Tamara Mazo 1 , Marina C. Munoz 2,5 , Fernando P. Dominici 2,5 , Maria C. Carreras 3,5 , Juan Jose Poderoso 3,5 , Junichi Sadoshima 4 and Ricardo J. Gelpi 1,5 1 Institute of Cardiovascular Physiopathology and Department of Pathology, Faculty of Medicine, University of Buenos Aires, Buenos Aires, Argentina 2 Institute of Chemistry and Biological Physical Chemistry, School of Pharmacy and Biochemistry, University of Buenos Aires, Buenos Aires, Argentina 3 Laboratory of Oxygen Metabolism, University Hospital, University of Buenos Aires, Buenos Aires, Argentina 4 Department of Cell Biology and Molecular Medicine, Rutgers New Jersey Medical School, Newark, NJ, USA 5 Member of the National Council of Scientific and Technological Research (CONICET), Buenos Aires, Argentina * These authors have contributed equally to this work Correspondence to: Ricardo J. Gelpi, email: // Keywords : myocardial infarction, ischemia/reperfusion, thioredoxin-1, middle-aged, Gerotarget Received : December 21, 2015 Accepted : January 30, 2016 Published : February 25, 2016 Abstract Thioredoxin-1 (Trx1) protects the heart from ischemia/reperfusion (I/R) injury. Given that the age at which the first episode of coronary disease takes place has considerably decreased, life at middle-aged (MA) emerges as a new field of study. The aim was determine whether infarct size, Trx1 expression and activity, Akt and GSK-3β were altered in young (Y) and MA mice overexpressing cardiac Trx1, and in a dominant negative (DN-Trx1) mutant of Trx1. Langendorff-perfused hearts were subjected to 30 minutes of ischemia and 120 minutes of reperfusion (R). We used 3 and 12 month-old male of wild type (WT), Trx1, and DN-Trx1. Trx1 overexpression reduced infarct size in young mice (WT-Y: 46.8±4.1% vs . Trx1-Y: 27.6±3.5%, p < 0.05). Trx1 activity was reduced by 52.3±3.2% ( p < 0.05) in Trx1-MA, accompanied by an increase in nitration by 17.5±0.9%, although Trx1 expression in transgenic mice was similar between young and middle-aged. The expression of p-Akt and p-GSK-3β increased during reperfusion in Trx1-Y. DN-Trx1 mice showed neither reduction in infarct size nor Akt and GSK-3β phosphorylation. Our data suggest that the lack of protection in Trx1 middle-aged mice even with normal Trx1 expression may be associated to decreased Trx1 activity, increased nitration and inhibition of p-Akt and p-GSK-3β.