Role of hyperoxic preconditioning in protection of cardiac tissue and arrhythmias following ischemia-reperfusion injury
Trauma Monthly: 13 (3); 211-222 Article Type: Research Article
T, Esmaeeli Dahaj
M, et al. Role of hyperoxic preconditioning in protection of cardiac tissue and arrhythmias following ischemia-reperfusion injury ,
Online ahead of Print
Objective:It has been previously documented that hyperoxia pretreatment protects the heart from ischemia-reperfusion injury. The present study was conducted to study the hypothesis that pre-exposure to normobaric hyperoxia reduces cardiomyocyte apoptotic cell death and arrhythmias following induction of ischemia-reperfusion in a rat model of regional coronary artery occlusion. Male wistar rats pretreated with normal air (21% O2, control, C) and 60 or 180 minutes of hyperoxia (H60 and H180) in hyperoxic chambers (≥95% O2), and the hearts were immediately isolated and perfused in a Langendorff apparatus. Hearts were subjected to 30 min of local ischemia followed by 120 min reperfusion. For examining the hyperoxia effects infarct size, percentage of myocytes apoptosis and ischemic arrhythmias were assessed. Material and Methods: Infarct size was reduced from 39.5±3.6 % in normoxic control group to 26.3±2.3 (p< 0.01) and 20.5±2.6 % (p< 0.001) in H60 and H180 groups respectively. Apoptosis was decreased by 180 min of hyperoxia (17.3±3.5% in H180 group vs. 31±2.3 % in control group, p< 0.05). 60 and 180 min of hyperoxia significantly attenuated total number of premature ventricular beats in ischemic phase (p< 0.05. Hyperoxia was also reduced VT and VF duration and number of VT episodes (p< 0.05). Accordingly, severity of arrhythmias (arrhythmia score) was lower in hyperoxia treated groups compared to control group (p< 0.05). Results: The results of present study indicate that hyperoxia pretreatment before heart ischemia and reperfusion reduces infarct size and attenuates cardiomyocyte apoptosis. Hyperoxia also significantly decreases severity of ischemic arrhythmias. Conclusion:
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