Unique morphological characteristics of mitochondrial subtypes in the heart: the effect of ischemia and ischemic preconditioning.
Unique morphological characteristics of mitochondrial subtypes in the heart: the effect of ischemia and ischemic preconditioning.
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DOI：
10.15190/d.2017.1
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发表时间：
2017-01-01
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影响因子：
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通讯作者：
Hausenloy, Derek J
中科院分区：
文献类型：
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作者：
Kalkhoran, Siavash Beikoghli;Munro, Peter;Hausenloy, Derek J
基本原理：在成人心肌细胞中已描述了三种线粒体亚群：肌原纤维间 (IMF)、肌膜下 (SSM) 和核周 (PN)。它们已被证明在生理学上存在差异，但它们在形态特征上是否也存在差异尚不清楚。众所周知，缺血预处理（IPC）可以预防急性心肌缺血/再灌注损伤（IRI）引起的线粒体功能障碍，但IPC是否也可以调节线粒体形态尚不清楚。目的：将研究成人心脏线粒体的三个不同亚群的形态特征以及缺血和IPC对线粒体形态的影响。方法：对小鼠心脏进行以下处理（每组N = 6）：仅稳定，IPC（3x5分钟循环）全身缺血和再灌注）、仅缺血（20 分钟全身缺血）；以及 IPC 和缺血。然后对心脏进行电子显微镜检查，并随后评估线粒体形态。结果：在成体心肌细胞中，发现 IMF 线粒体比 PN 和 SSM 线粒体更长且球形度更小。与其他两个子集相比，PN 线粒体尺寸较小。 SSM 线粒体的面积与 IMF 线粒体相似，但其球形度与 PN 线粒体相似。研究表明，缺血会增加所有 3 个线粒体亚群的球形参数；减少 IMF 线粒体的长度，增加 PN 线粒体的大小。 IPC 对基线时或缺血后的线粒体形态没有影响。结论：成人心脏中线粒体的三个亚群在形态上是不同的。 IPC 似乎不会调节成人心肌细胞的线粒体形态。
RATIONALE: Three subsets of mitochondria have been described in adult cardiomyocytes - intermyofibrillar (IMF), subsarcolemmal (SSM), and perinuclear (PN). They have been shown to differ in physiology, but whether they also vary in morphological characteristics is unknown. Ischemic preconditioning (IPC) is known to prevent mitochondrial dysfunction induced by acute myocardial ischemia/reperfusion injury (IRI), but whether IPC can also modulate mitochondrial morphology is not known.AIMS: Morphological characteristics of three different subsets of adult cardiac mitochondria along with the effect of ischemia and IPC on mitochondrial morphology will be investigated.METHODS: Mouse hearts were subjected to the following treatments (N=6 for each group): stabilization only, IPC (3x5 min cycles of global ischemia and reperfusion), ischemia only (20 min global ischemia); and IPC and ischemia. Hearts were then processed for electron microscopy and mitochondrial morphology was assessed subsequently.RESULTS: In adult cardiomyocytes, IMF mitochondria were found to be more elongated and less spherical than PN and SSM mitochondria. PN mitochondria were smaller in size when compared to the other two subsets. SSM mitochondria had similar area to IMF mitochondria but their sphericity measures were similar to PN mitochondria. Ischemia was shown to increase the sphericity parameters of all 3 subsets of mitochondria; reduce the length of IMF mitochondria, and increase the size of PN mitochondria. IPC had no effect on mitochondrial morphology either at baseline or after ischemia.CONCLUSION: The three subsets of mitochondria in the adult heart are morphologically different. IPC does not appear to modulate mitochondrial morphology in adult cardiomyocytes.