Intramyocardial injection of thioredoxin 2-expressing lentivirus alleviates myocardial ischemia-reperfusion injury in rats

The aim of this study is to explore the role of thioredoxin-2 (Trx2) in autophagy and apoptosis during myocardial ischemia-reperfusion (I/R) injury in vivo. In the study, adult male Sprague-Dawley rats were assigned to four groups at random and pretreated with normal saline (sham operation and I/R groups) and either a control lentivirus (Lv-GFP-N) or one expressing Trx2 (Lv-GFP-Trx2). Sevendays after pretreatment, rat MIRI models were produced via occlusion of the left anterior descending coronary artery for 30 min followed by reperfusion for 6 h. Hearts and blood were harvested to assess efficiency of lentivirus transfection via immunofluorescence staining, quantitative RT-PCR and western blotting, oxidative stress via the malondialdehyde level and superoxide dismutase activity, myocardial damage via myocardial enzymelevels and histopathological staining, myocardial apoptosis via TUNEL assays and western blotting, and myocardial autophagy viawestern blotting. Our results showed thatthe delivery of Lv-GFP-Trx2 into the myocardium remarkably increased Trx2 expression. The upregulation of Trx2 contributed to alleviation of oxidative stress, attenuation of myocardial histological damage, reduced leakage of myocardial enzyme and decrease in infarct size. Moreover, the overexpression of Trx2 was significantly associated with thedecreased incidence of apoptosis via ASK1-dependent intrinsic mitochondrial apoptotic pathwayand autophagy via the mammalian target of rapamycin (mTOR) pathway. The study indicates that upregulation of Trx2 protectsthe myocardium from MIRI and isinvolved inthe inhibition of apoptosis and autophagy. Therefore, Trx2 isa promising therapeutic strategy for attenuating MIRI.