Heise K, Estevez M S, Puntarulo S, Galleano M, Nikinmaa M, Pörtner H O, Abele D
Alfred-Wegener-Institute for Polar and Marine Research, Am Handelshafen 12, 27570, Bremerhaven, Germany.
J Comp Physiol B. 2007 Oct;177(7):765-77. doi: 10.1007/s00360-007-0173-4. Epub 2007 Jun 20.
Acute, short term cooling of North Sea eelpout Zoarces viviparus is associated with a reduction of tissue redox state and activation of hypoxia inducible factor (HIF-1) in the liver. The present study explores the response of HIF-1 to seasonal cold in Zoarces viviparus, and to latitudinal cold by comparing the eurythermal North Sea fish to stenothermal Antarctic eelpout (Pachycara brachycephalum). Hypoxic signalling (HIF-1 DNA binding activity) was studied in liver of summer and winter North Sea eelpout as well as of Antarctic eelpout at habitat temperature of 0 degrees C and after long-term warming to 5 degrees C. Biochemical parameters like tissue iron content, glutathione redox ratio, and oxidative stress indicators were analyzed to see whether the cellular redox state or reactive oxygen species formation and HIF activation in the fish correlate. HIF-1 DNA binding activity was significantly higher at cold temperature, both in the interspecific comparison, polar vs. temperate species, and when comparing winter and summer North Sea eelpout. Compared at the low acclimation temperatures (0 degrees C for the polar and 6 degrees C for the temperate eelpout) the polar fish showed lower levels of lipid peroxidation although the liver microsomal fraction turned out to be more susceptible to lipid radical formation. The level of radical scavenger, glutathione, was twofold higher in polar than in North Sea eelpout and also oxidised to over 50%. Under both conditions of cold exposure, latitudinal cold in the Antarctic and seasonal cold in the North Sea eelpout, the glutathione redox ratio was more oxidised when compared to the warmer condition. However, oxidative damage parameters (protein carbonyls and thiobarbituric acid reactive substances (TBARS) were elevated only during seasonal cold exposure in Z. viviparus. Obviously, Antarctic eelpout are keeping oxidative defence mechanisms high enough to avoid accumulation of oxidative damage products at low habitat temperature. The paper discusses how HIF could be instrumental in cold adaptation in fish.
北海绵鳚（Zoarces viviparus）的急性短期降温与肝脏组织氧化还原状态的降低以及缺氧诱导因子（HIF-1）的激活有关。本研究通过比较广温性的北海鱼类和狭温性的南极绵鳚（Pachycara brachycephalum），探讨了HIF-1对绵鳚季节性寒冷和纬度性寒冷的反应。在夏季和冬季北海绵鳚以及南极绵鳚的肝脏中，研究了在栖息地温度为0摄氏度时以及长期升温至5摄氏度后的缺氧信号（HIF-1 DNA结合活性）。分析了组织铁含量、谷胱甘肽氧化还原比和氧化应激指标等生化参数，以了解鱼类细胞的氧化还原状态或活性氧生成与HIF激活之间是否存在关联。无论是在种间比较（极地与温带物种）中，还是在比较冬季和夏季北海绵鳚时，低温下HIF-1 DNA结合活性均显著更高。在低驯化温度下（极地绵鳚为0摄氏度，温带绵鳚为6摄氏度）进行比较时，极地鱼类的脂质过氧化水平较低，尽管肝脏微粒体部分对脂质自由基形成更敏感。自由基清除剂谷胱甘肽的水平在极地绵鳚中比北海绵鳚高出两倍，并且氧化程度超过50%。在两种冷暴露条件下，即南极的纬度性寒冷和北海绵鳚的季节性寒冷，与较温暖条件相比，谷胱甘肽氧化还原比的氧化程度更高。然而，氧化损伤参数（蛋白质羰基和硫代巴比妥酸反应性物质（TBARS））仅在绵鳚季节性冷暴露期间升高。显然，南极绵鳚保持了足够高的氧化防御机制，以避免在低栖息地温度下氧化损伤产物的积累。本文讨论了HIF如何有助于鱼类的冷适应。
