Department of Cellular Biochemistry and Human Genetics, The Hebrew University-Hadassah Schools of Medicine and Dental Medicine, Ein Kerem, Jerusalem, Israel.
Biochem Biophys Res Commun. 2012 Nov 23;428(3):376-82. doi: 10.1016/j.bbrc.2012.10.062. Epub 2012 Oct 24.
Reports about the effect of ischemia and reperfusion on specific activities of the respiratory chain are often discrepant. One of the factors that govern this discrepancy is that typical mechanical procedures for mitochondrial isolation yield largely sub-sarcolemmal mitochondria (SSM), while the interfibrillar mitochondria (IFM), which provide most of the energy for the contractile apparatus, are under-represented. Here we investigated the impact of myocardial ischemia and reperfusion on SSM and IFM separately. Thirty-two Wister rats were randomly divided into four groups: control groups, ischemia groups, reperfusion groups and precondition groups. SSM and IFM were isolated from the rats' hearts from all the groups. The mitochondrial membrane potential (Δψ) and swelling were assessed at energized (using either 5mM succinate or 5mM glutamate and 5mM malate (GM) as a substrate) and non-energized conditions, where IFM showed better resistance to change in both conditions. Results showed that IFM have a higher coupling efficiency than SSM when energized by GM, but lower than SSM when energized with succinate. Preconditioning the rats' hearts prior to ischemia or reperfusion preserved the physiological and biochemical functions of both IFM and SSM and are energy dependent. The distinct physiological-biochemical functions of the mitochondrial sub-populations during ischemia and reperfusion depend on the overall energy status of the mitochondrial sub-population.
关于缺血再灌注对呼吸链特定活性影响的报告往往存在差异。导致这种差异的因素之一是，典型的线粒体分离机械程序主要产生肌小节下的线粒体（SSM），而提供大部分收缩装置能量的纤维间线粒体（IFM）则代表性不足。在这里，我们分别研究了心肌缺血再灌注对 SSM 和 IFM 的影响。32 只 Wister 大鼠随机分为四组：对照组、缺血组、再灌注组和预处理组。从所有组的大鼠心脏中分离出 SSM 和 IFM。在有能（使用 5mM 琥珀酸或 5mM 谷氨酸和 5mM 苹果酸（GM）作为底物）和无能条件下评估线粒体膜电位（Δψ）和肿胀，IFM 在这两种条件下显示出更好的抗变化能力。结果表明，IFM 在 GM 供能时的偶联效率高于 SSM，但在琥珀酸供能时则低于 SSM。在缺血或再灌注前对大鼠心脏进行预处理可维持 IFM 和 SSM 的生理和生化功能，且依赖于能量。在缺血再灌注过程中，线粒体亚群的不同生理生化功能取决于线粒体亚群的整体能量状态。
