Akiyama Y, Garcia R E, Bazzy A R
Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut 06510, USA.
Am J Physiol. 1996 Aug;271(2 Pt 1):L320-5. doi: 10.1152/ajplung.1996.271.2.L320.
We have previously shown that respiratory training with inspiratory flow-resistive (IFR) loads improves diaphragm performance and is associated with an increase in cytochrome-c oxidase (COX) activity (1). The present study was conducted to define the level at which the increase in COX activity is controlled. Six sheep were trained with IFR loads for 3 h/day for 3 wk. The diaphragm was sampled from the six trained sheep and from six control sheep. Quantitative DNA and RNA slot-blot analyses with mitochondrially coded COX subunit III and nuclearly coded subunit IV probes and immunoblotting with anti-COX holoenzyme antibodies were performed. We found that in the diaphragm the amount of COX subunit proteins coded in either genetic system was greater in the trained than in the control sheep. Neither the amount of mitochondrial DNA nor mRNA for COX subunits was different between the two groups. We conclude that the increase in COX activity in the diaphragm after chronic respiratory training is determined by the amount of subunit proteins, possibly involving translation/degradation of these proteins.
我们之前已经表明，采用吸气气流阻力（IFR）负荷进行呼吸训练可改善膈肌功能，并与细胞色素c氧化酶（COX）活性增加有关（1）。本研究旨在确定COX活性增加受控制的水平。六只绵羊每天接受3小时的IFR负荷训练，持续3周。从六只经过训练的绵羊和六只对照绵羊身上采集膈肌样本。使用线粒体编码的COX亚基III和核编码的亚基IV探针进行定量DNA和RNA斑点印迹分析，并用抗COX全酶抗体进行免疫印迹分析。我们发现，在膈肌中，无论是哪种遗传系统编码的COX亚基蛋白数量，训练组绵羊都比对照组绵羊更多。两组之间线粒体DNA的数量以及COX亚基的mRNA均无差异。我们得出结论，长期呼吸训练后膈肌中COX活性的增加是由亚基蛋白的数量决定的，可能涉及这些蛋白质的翻译/降解过程。
