Aldakkak Mohammed, Stowe David F, Chen Qun, Lesnefsky Edward J, Camara Amadou K S
Anesthesiology Research Laboratories, Department of Anesthesiology, The Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA.
Cardiovasc Res. 2008 Jan 15;77(2):406-15. doi: 10.1016/j.cardiores.2007.08.008.
Damage to the mitochondrial electron transport chain (ETC) occurs during ischaemia. Blockade of electron flow in the ETC just before ischaemia with the reversible complex I inhibitor amobarbital protects isolated mitochondria against ischaemic damage and preserves oxidative phosphorylation and cytochrome c content. We hypothesized that brief amobarbital perfusion just before ischaemia would improve cardiac recovery and decrease infarct size after ischaemia and reperfusion (IR) by preserving the mitochondrial redox state and reducing mitochondrial superoxide (O(2)(-*)) generation, in turn would decrease mitochondrial Ca(2+) accumulation (mt[Ca(2+)]).
Guinea pig Langendorff-perfused hearts were treated with Krebs Ringer solution (KR; untreated) or amobarbital (2.5 mM) in KR for 1 min immediately before 30 min of no flow, global ischaemia, followed by reperfusion without additional treatment. Cardiac function, mitochondrial NADH, FAD, mt[Ca(2+)], and O(2)(-*) levels were assessed during the 1 min perfusion period and throughout IR.
Amobarbital perfusion alone before ischaemia significantly increased O(2)(-) levels and NADH, without altering FAD, and decreased mt[Ca(2+)]. During ischaemia, mitochondrial NADH was higher, O(2)(-) levels were lower, and mt[Ca(2+)] was less elevated in the amobarbital group. On reperfusion O(2)(-*) levels and mt[Ca(2+)] were significantly reduced, NADH-FAD redox state was preserved and cardiac function was markedly improved in the amobarbital group; infarct size was smaller in the amobarbital group compared to the untreated group.
Temporary blockade of mitochondrial complex I activity by amobarbital protects hearts by reducing production of O(2)(-*) and mtCa(2+) loading during IR injury.
线粒体电子传递链（ETC）在缺血期间会受到损伤。在缺血前用可逆性复合物I抑制剂异戊巴比妥阻断ETC中的电子流，可保护分离的线粒体免受缺血损伤，并维持氧化磷酸化和细胞色素c含量。我们假设，在缺血前进行短暂的异戊巴比妥灌注可通过维持线粒体氧化还原状态和减少线粒体超氧阴离子（O(2)(-*)）生成来改善心脏恢复并减小缺血再灌注（IR）后的梗死面积，进而减少线粒体Ca(2+)蓄积（mt[Ca(2+)]）。
豚鼠离体心脏用Langendorff灌流，在30分钟无血流的全心缺血前1分钟，用Krebs-Ringer溶液（KR；未处理）或含2.5 mM异戊巴比妥的KR溶液处理，随后不进行额外处理直接进行再灌注。在1分钟灌注期及整个IR过程中评估心脏功能、线粒体NADH、FAD、mt[Ca(2+)]和O(2)(-*)水平。
缺血前单独进行异戊巴比妥灌注可显著提高O(2)(-)水平和NADH，而不改变FAD，并降低mt[Ca(2+)]。在缺血期间，异戊巴比妥组线粒体NADH较高，O(2)(-)水平较低，mt[Ca(2+)]升高较少。再灌注时，异戊巴比妥组O(2)(-*)水平和mt[Ca(2+)]显著降低，NADH-FAD氧化还原状态得以维持，心脏功能明显改善；与未处理组相比，异戊巴比妥组梗死面积较小。
异戊巴比妥对线粒体复合物I活性的短暂阻断通过减少IR损伤期间O(2)(-*)的产生和mtCa(2+)的负荷来保护心脏。
