| Abstract
| - Objective:. Coenzyme Q10 has been found to enhance recovery of function after reperfusion in numerous experimental acute ischemia-reperfusion models. We assessed whether coenzyme Q10, administered intravenously either during or 1 h before ischemia, can limit infarct size in the rabbit. Methods: Anesthetized open-chest rabbits were subjected to 30 min of coronary artery occlusion and 4 h of reperfusion. In Protocol 1, 12 min after beginning of ischemia rabbits were randomized to intravenous infusion of 30 mg coenzyme Q10 (Eisai Co., Japan) (n = 10) or vehicle (n = 10). In Protocol 2, rabbits were randomized to 30 mg coenzyme Q10 (n = 6) or vehicle (n = 6) treatment 60 min before ischemia. Ischemic zone at risk (IZ) was assessed by blue dye and necrotic zone (NZ) by tetrazolium staining. Results: In both protocols, coenzyme Q10 did not alter heart rate, mean blood pressure, or regional myocardial blood flows in either the ischemic or non-ischemic zones during ischemia or reperfusion. No difference was found in IZ (as fraction of LV weight) (Protocol 1: 0.24 ± 0.02 vs. 0.25 ± 0.02; Protocol 2: 0.28 ± 0.02 vs. 0.28 ± 0.03, in the control vs. coenzyme Q10 groups, respectively). The NZ/IZ ratio was comparable between the groups in both protocols (Protocol 1: 0.22 ± 0.04 vs. 0.26 ± 0.04; Protocol 2: 0.21 ± 0.06 vs. 0.30 ± 0.06, in the control vs. coenzyme Q10 groups, respectively). Conclusions: Coenzyme Q10, administered acutely either during or 60 min before myocardial ischemia, does not attenuate infarct size in the rabbit.
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