猫心肌和骨骼肌中的组织特异性和底物特异性线粒体生物能量学

Tissue-specific and substrate-specific mitochondrial bioenergetics in feline cardiac and skeletal muscles

Keywords：feline, heart, mitochondria, oxidative phosphorylation, skeletal muscl

关键词：猫科动物, 心脏, 线粒体, 氧化磷酸化, 骨骼肌

哺乳动物：猫

作者：Christiansen LB, Dela F, Koch J, Yokota T

出版期刊：《Journal of Veterinary Medical Science》 2015/2/11

Abstract：

No studies have investigated the mitochondrial function in permeabilized muscle fiber from cats. The aim of this study was to investigate tissue-specific and substrate-specific characteristics of mitochondrial oxidative phosphorylation (OXPHOS) capacity in feline permeabilized oxidative muscle fibers. Biopsies of left ventricular cardiac muscle and soleus muscle, a type I-rich oxidative skeletal muscle, were obtained from 15 healthy domestic cats. Enzymatic activity of citrate synthase (CS), a biomarker of mitochondrial content, was measured. Mitochondrial OXPHOS capacity with various kinds of non-fatty-acid substrates and fatty-acid substrate in permeabilized muscle fiber was measured by using high-resolution respirometry. CS activity in the heart was 3 times higher than in the soleus muscle. Mitochondrial state 3 respiration, ADP-stimulated respiration, with complex I-linked and complex I+II-linked substrates, respectively, was significantly higher in the heart than in the soleus muscle when normalized for muscle mass, but not for CS activity, indicating that greater capacity for mitochondrial OXPHOS with these non-fatty-acid substrates in the heart may depend on higher mitochondrial content. In contrast, the soleus muscle had higher mitochondrial state 3 respiration with fatty acids than the heart when normalized for CS activity, indicating greater capacity for fatty-acid oxidation per mitochondrion in the soleus. Our findings suggest that there are tissue- specific and substrate-specific quantitative and qualitative differences in mitochondrial OXPHOS capacity between the different types of oxidative muscles from cats.

文章摘要：

没有研究调查过猫的透化肌纤维中的线粒体功能。本研究的目的是研究猫透化氧化肌纤维中线粒体氧化磷酸化 (OXPHOS) 能力的组织特异性和底物特异性特征。从 15 只健康的家猫身上获得了左心室心肌和比目鱼肌（一种富含 I 型的氧化骨骼肌）的活组织检查。柠檬酸合酶 (CS) 的酶活性是线粒体含量的生物标志物。使用高分辨率呼​​吸测量法测量透化肌纤维中各种非脂肪酸底物和脂肪酸底物的线粒体 OXPHOS 能力。心脏中的 CS 活性是比目鱼肌中的 3 倍。线粒体状态 3 呼吸，ADP 刺激的呼吸，分别具有复杂的 I 连接和复杂 I+II 连接的底物，当肌肉质量归一化时，心脏中的呼吸显着高于比目鱼肌，但 CS 活动没有，表明心脏中这些非脂肪酸底物对线粒体 OXPHOS 的更大容量可能取决于更高的线粒体含量。相比之下，当对 CS 活性进行归一化时，比目鱼肌的线粒体状态 3 与脂肪酸的呼吸比心脏更高，这表明比目鱼肌中每个线粒体的脂肪酸氧化能力更强。我们的研究结果表明，猫不同类型的氧化肌肉之间的线粒体 OXPHOS 能力存在组织特异性和底物特异性的定量和定性差异。

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