ABSTRACT
Inflammation has been implicated in the pathogenesis of myocardial ischemia/reperfusion (I/R) injury (MIRI). Previous studies have confirmed that deleted in esophageal cancer 1 (DEC1) is an important transcription factor in inflammation. However, the role of DEC1 in MIRI remains unclear. The present study aimed to determine whether the downregulation of DEC1 by RNA interference alleviated inflammation to protect against MIRI. Adult Sprague-Dawley rats (n=48) were randomly divided into four groups: Sham; I/R; adenovirus expressing green fluorescent protein control (Ad-G-Control); and DEC1-targeting RNA interference (Ad-G-DEC1) groups. Following gene delivery 4 days later, the rat myocardial I/R model was established and myocardial enzymes [creatine kinase (CK) and lactate dehydrogenase (LDH)] were detected. Hematoxylin and eosin (H&E) staining was performed to evaluate the myocardial damage and the infarct area was assessed using Evans Blue/triphenyltetrazolium chloride staining. The inflammatory mediators interleukin (IL)-ß and tumor necrosis factor (TNF)-α were also detected using ELISA kits to assess the inflammatory response. Finally, western blotting and reverse transcription-quantitative PCR were used to analyze the expression levels of associated proteins and mRNAs. Ad-G-DEC1 RNA interference markedly decreased DEC1 expression levels. In addition, following the downregulation of DEC1 expression, the infarct size, CK, LDH, Toll-like receptor (TLR)4, NF-κB, IL-ß and TNF-α levels were all significantly decreased. In conclusion, the results of the present study suggested that the downregulation of DEC1 may decrease the inflammation by suppressing the TLR4/NF-κB signaling pathway, which may represent a therapeutic target for MIRI.
ABSTRACT
During the processes of myocardial ischemia reperfusion (I/R) injury, inflammation and apoptosis play an important role. I/R and its induced acute myocardial infarction (AMI) with high morbidity and mortality, and there is no effective treatment for it so far. TRAF5 has been shown to regulate inflammation and apoptosis in atherosclerosis, steatosis and melanoma cells, but its function in myocardial I/R injury is still unclear. This study demonstrates that the expression of TRAF5 is significant up-regulation in heart tissues of I/R injury mice and hypoxia/reoxygenation (H/R)-stimulated cardiomyocytes. TRAF5 knockout mice exhibites heavier heart damage, inflammatory response and cell death after myocardial I/R injury. Further, TRAF5 overexpression inhibites inflammation and apoptosis of H/R-stimulated cardiomyocytes. Mechanistically, we prove that TRAF5 promotes the activation of AKT. Overall, our study indicates that TRAF5 can regulate the processes of myocardial I/R injury. TRAF5 can be a new therapy target for myocardial I/R injury.
