Coenzyme Q10 (
CoQ10,
ubiquinone) has been shown to be protective against
myocardial ischemia/reperfusion induced injury. The purpose of this study was to investigate the effect of
CoQ10 added to cold cristalloid
cardioplegia on hypothermic
ischemia and normothermic reperfusion using an isolated working rat heart. Hearts (n = 6-9/group) from male Wistar rats were aerobically (37 degrees C) perfused (20 min) with
bicarbonate buffer. This was followed by a 3-min infusion of
St. Thomas' Hospital cardioplegic solution containing various concentrations of
CoQ10 (0, 1, 3, 6, 12, and 58 mumol/L). Hearts were then subjected to 180 min of hypothermic (20 degrees C) global
ischemia and 35 min of normothermic (37 degrees C) reperfusion (15 min Langendorff, 20 min working).
Ventricular fibrillation (Vf) upon reperfusion was irreversible in the 12 and 58 mumol/ L
CoQ10 groups (4/6 and 3/6, respectively). In the hearts which Vf upon reperfusion was not irreversible, the percent recovery of aortic flow (%AF) was 43.3 +/- 5.4% (n = 9) in the control group versus 31.6 +/- 7.7% (n = 6), 38.0 +/- 12.0% (n = 6), 27.2 +/- 6.9% (n = 6), 31.3% (n = 2), and 30.4 +/- 14.2% (n = 3) in the 1, 3, 6, 12, and 58 mumol/L
CoQ10 groups, respectively.
Creatine kinase leakage during Langendorff reperfusion tended to be greater in the 12 and 58 mumol/L
CoQ10 groups than in the control group. Thus,
CoQ10 in the cold cristalloid
cardioplegic solution induced irreversible Vf upon reperfusion and failed to improve functional recoveries following hypothermic global
ischemia.