Abstract 33: The Effects of Global Ischemia/Reperfusion Injury on Expressions of Kappa-Opioid Receptor in Myocardium in Cardiac Arrest and Cardiopulmonary Rats
Objective: The effects of global ischemia/reperfusion injury on expressions of κeappa opioid receptor (κe-OR) mRNA and protein in myocardium were investigated in cardiac arrest (CA) and cardiopulmonary resuscitation (CPR) rats.
Methods: 114 male SD rats were randomized into 4 groups; 1) AS5 group (n=36), 5min of asphyxia before CPR; 2) AS6 group (n=36), 6 min of asphyxia before CPR; 3) AS7 group (n=36), 7min of asphyxia before CPR; and 4) Control group (n=6). Asphyxia-induced CA was performed by turning-off the ventilator and clamping the endotracheal tube. Chest compressions and mechanical ventilations were started after 5 min, 6min or 7min of asphyxia,respectively. The hemodynamic data of HR, MAP, dP/dt40, LVEDP and -dP/dtmax were continuously recorded. The CA/CPR rat hearts were harvested at 0h, 0.5h, 2h, 4h, 6h and 24h after resuscitation;the control hearts were harvest at 0.5h after animal preparation. The expressions of κe-OR mRNA and protein in myocardium were detected by methods of RT-PCR and western blot, respectively.
Results: The severity of postresuscitaion myocardium dysfunction was remarkably increased in AS6 and AS7 group, in comparison to AS5 group (P<0.01). The postresuscitation myocardial dysfunction could not reverse to normal at 24h after resuscitation in AS7 group(P<0.05). The expressions of κe-OR mRNA and protein in myocardium were significantly increased after CA/CPR (P<0.01). Among CA/CPR rats, the κe-OR expressions were highest in AS6 group, but lowest in AS7 group (P<0.01,figure 1).
Conclusions: The expressions of κe-OR in myocardium were significantly upregulated after CA/CPR. The κe-OR expressions were further increased when the I/R injury was more severe. However, this upregulation effect was no more observed when the postresuscitation myocardial dysfunction worsened to irreversible.
- © 2010 by American Heart Association, Inc.