Department of Biology, University of Naples Federico II, Complesso Universitario Monte Sant'Angelo, Via Cinthia, 80126, Naples, Italy.
J Comp Physiol B. 2019 Feb;189(1):97-108. doi: 10.1007/s00360-018-1198-6. Epub 2018 Dec 17.
Rapid fluctuations of the oxygen content of both natural and anthropogenic origin are relatively common in freshwater environments. Fish adaptation to these conditions implies tolerance of both low levels of oxygen availability and reoxygenation. Hypoxia tolerance in fish has been widely studied, but the involvement of mitochondria in the response of fish to rapid hypoxia/reoxygenation stress is less known. Zebrafish, a floodplain species, is likely facing significant changes in dissolved oxygen in its natural environment and displays a moderate ability to tolerate hypoxia. In the present study, we report the effects of an acute hypoxia/reoxygenation stress (H/R) protocol on mitochondrial functionality (respiration, complex activities, rate of HO release) and redox state (level of HPs and protein oxidation) of muscle tissue. In parallel, the animal metabolic performance (routine metabolism, nitrogen excretion and swimming performance) was measured. Additionally, the recovery from H/R was tested 20 h after treatment. A significant stimulation by H/R of muscle mitochondrial respiration and HO release was observed, which was only in part counteracted by stimulation of the antioxidant system, resulting in an increased level of lipid peroxides and protein carbonyls. In parallel, H/R increased the animal oxygen consumption and urea excretion rate and reduced routine activity. A significant strong reduction of endurance at 80% U was also observed. Most of the altered parameter did not recover 20 h after reoxygenation. These data indicate a significant alteration of zebrafish muscle mitochondrial state after acute H/R, associated with changes in tissue redox state and locomotor performance.
快速波动的氧气含量的自然和人为来源是比较常见的在淡水环境中。鱼类适应这些条件意味着耐受低水平的氧气供应和再氧化。鱼类的耐缺氧能力已被广泛研究，但线粒体在鱼类对快速缺氧/复氧应激的反应中的参与知之甚少。斑马鱼是一种洪泛区物种，在其自然环境中可能面临溶解氧的显著变化，并显示出中度耐受缺氧的能力。在本研究中，我们报告了急性缺氧/复氧应激（H/R）方案对肌肉组织线粒体功能（呼吸、复合物活性、HO 释放率）和氧化还原状态（HPs 水平和蛋白质氧化）的影响。同时，测量了动物的代谢性能（基础代谢率、氮排泄和游泳性能）。此外，还测试了处理后 20 小时的 H/R 恢复情况。观察到 H/R 显著刺激肌肉线粒体呼吸和 HO 释放，这部分被抗氧化系统的刺激所抵消，导致脂质过氧化物和蛋白质羰基水平增加。同时，H/R 增加了动物的耗氧量和尿素排泄率，并降低了基础代谢率。还观察到 80%U 耐力的显著强烈降低。大多数改变的参数在再氧化 20 小时后没有恢复。这些数据表明，急性 H/R 后斑马鱼肌肉线粒体状态发生了显著改变，与组织氧化还原状态和运动性能的变化有关。
