Filice Mariacristina, Caferro Alessia, Gattuso Alfonsina, Sperone Emilio, Agnisola Claudio, Faggio Caterina, Cerra Maria Carmela, Imbrogno Sandra
Dept. of Biology, Ecology and Earth Sciences, University of Calabria, Rende, Italy.
Dept. of Biology, Ecology and Earth Sciences, University of Calabria, Rende, Italy.
J Contam Hydrol. 2024 Feb;261:104299. doi: 10.1016/j.jconhyd.2024.104299. Epub 2024 Jan 12.
The skeletal muscle is a highly plastic tissue. Its ability to respond to external stimuli and challenges allows it to face the functional needs of the organism. In the goldfish Carassius auratus, a model of hypoxia resistance, exposure to reduced oxygen is accompanied by an improvement of the swimming performance, relying on a sustained contractile behavior of the skeletal muscle. At the moment, limited information is available on the mechanisms underlying these responses. We here evaluated the effects of short- (4 days) and long- (20 days) term exposure to moderate water hypoxia on the goldfish white skeletal muscle, focusing on oxidative status and mitochondrial dynamics. No differences in lipid peroxidation, measured as 2-thiobarbituric acid-reacting substances (TBARS), and oxidatively modified proteins (OMP) were detected in animals exposed to hypoxia with respect to their normoxic counterparts. Exposure to short-term hypoxia was characterized by an enhanced SOD activity and expression, paralleled by increased levels of Nrf2, a regulator of the antioxidant cell response, and HSP70, a chaperone also acting as a redox sensor. The expression of markers of mitochondrial biogenesis (TFAM) and abundance (VDAC) and of the mtDNA/nDNA ratio was similar under normoxia and under both short- and long-term hypoxia, thus excluding a rearrangement of the mitochondrial apparatus. Only an increase of PGC1α (a transcription factor involved in mitochondrial dynamics) was detected after 20 days of hypoxia. Our results revealed novel aspects of the molecular mechanisms that in the goldfish skeletal muscle may sustain the response to hypoxia, thus contributing to adequate tissue function to organism requirements.
骨骼肌是一种高度可塑性的组织。它对外部刺激和挑战作出反应的能力使其能够满足机体的功能需求。在抗缺氧模型金鱼中，暴露于低氧环境会伴随着游泳性能的改善，这依赖于骨骼肌持续的收缩行为。目前，关于这些反应背后机制的信息有限。我们在此评估了短期（4天）和长期（20天）暴露于中度水体低氧对金鱼白色骨骼肌的影响，重点关注氧化状态和线粒体动力学。在暴露于低氧环境的动物中，与常氧对照动物相比，未检测到以硫代巴比妥酸反应物质（TBARS）衡量的脂质过氧化和氧化修饰蛋白（OMP）的差异。短期低氧暴露的特征是超氧化物歧化酶（SOD）活性和表达增强，同时抗氧化细胞反应调节因子Nrf2以及同样作为氧化还原传感器的伴侣蛋白HSP70的水平升高。在常氧以及短期和长期低氧条件下，线粒体生物发生标志物（线粒体转录因子A，TFAM）的表达、丰度标志物（电压依赖性阴离子通道，VDAC）以及线粒体DNA与核DNA的比率均相似，因此排除了线粒体结构的重排。仅在低氧20天后检测到过氧化物酶体增殖物激活受体γ共激活因子1α（PGC1α，一种参与线粒体动力学的转录因子）增加。我们的结果揭示了金鱼骨骼肌中可能维持对低氧反应的分子机制的新方面，从而有助于使组织功能满足机体需求。
