Abstract 1570: Cardioprotection With Red Wine Polyphenol [rwp] Is Regulated By Intracellular Redox Changes Through Thioredoxin
Although epidemiological evidence indicates that regular consumption of moderate amount wine maintains a healthy heart, precise mechanism remains unknown. We determined the changes in intracellular redox environment of the heart during ischemia and reperfusion [I/R] and the effects of RWP on such changes. Since redox regulation by thioredoxin (Trx) plays a crucial role in cytoprotection, the effects of RWP on Trx were monitored. The rats were divided into four groups: I: control; II: 2.5 mg/kg RWP/day for 10 days; III: RWP+shRNA against Trx-1, IV: RWP+cisplatin (1 mg/kg). In concert, two groups of mice (Dominant negative mutant-Dn-Trx-1) and corresponding wild type groups were fed 2.5 mg/kg RWP. After 10 days, isolated hearts were made ischemic for 30 min followed by 2 h of reperfusion. I/R developed an infarct size of about 40%, and resulted about 25% apoptotic cardiomyocytes, which were reduced by resveratrol. Cisplatin, but not shRNA-Trx-1 abolished the cardioprotective abilities of resveratrol. Malonaldehyde [MDA] formation, a presumptive marker for lipid peroxidation, was increased in I/R group, reduced in resveratrol group, and resveratrol-mediated reduction in MDA formation was abolished with cisplatin, but not with shRNA-Trx-1. I/R-induced reduction in GSH/GSSH ratio was prevented by resveratrol, and resveratrol mediated preservation of GSH/GSSG ration was reduced by cisplatin, but not with sh-RNA-Trx-1. RT-PCR revealed an increase in both Trx-1 and Trx-2 transcripts, but only Trx-2 protein, but not Trx-1 protein, was enhanced with resveratrol. In the experiments with Dn-Trx-1, resveratrol reduced I/R-mediated increase in infarct size and apoptosis. EPR study revealed an increase in the decay rates of the nitroxide radical with RWP treatment vs. control hearts suggesting an increase in the redox status of the RWP heart. Finally, RWP generated a survival signal by the phosphorylation of Akt and increased in an induction of Bcl-2 expression, which was inhibited with cisplatin, but not with shRNA-Trx-1. The results indicate RWP provides cardioprotection by maintaining intracellular redox environments, and Trx-2 plays a role in switching I/R-induced death signal into survival signal.