Blagojević Dusko P
Institute for Biological Research, Department for Physiology, Bulevar despota Stefana 142, 11060 Belgrade, Serbia.
Cryo Letters. 2007 May-Jun;28(3):137-50.
Hetero and endothermic adaptive responses arising as a result of natural responses to environmental cues include antioxidant systems that support adaptations to environmental low temperatures in the broadest sense. These temperatures induce phase changes in energy production and consequently changes in the concentration of reactive oxygen species (ROS). The latter may lead to oxidative stress and the impairment of cellular homeostasis and antioxidant defence systems (ADS) scavenge the ROS so generated. In endotherms the ADS responds to oxidative pressure during acute cold stress conditions, this response is tissue specific and does not extend to prevent other oxidative damage. The early acute phase of cold exposure is accompanied by a significant depletion in redox equivalents. Under such conditions it is questionable if ADS has the capacity to neutralize elevated levels of ROS since there is also an increased energy demand and enhanced ATP consumption. Prolonged exposure to cold leads to ADS adaptation. Hibernators and freeze-tolerant species elevate their ADS before hibernation or freezing in order to prepare for and cope with re-awakening. The involvement of ROS and the role of the ADS in organisms subjected to low temperatures are features intercalated into physiological mechanisms of homestasis. The exact mechanisms for ADS regulation have not been fully defined and are the subject of many ongoing intriguing scientific investigations.
由于对环境线索的自然反应而产生的异源和吸热适应性反应包括抗氧化系统，从最广泛的意义上来说，这些系统支持对环境低温的适应。这些温度会引起能量产生的相变，进而导致活性氧（ROS）浓度的变化。后者可能导致氧化应激以及细胞稳态的受损，而抗氧化防御系统（ADS）会清除如此产生的ROS。在恒温动物中，ADS在急性冷应激条件下对氧化压力作出反应，这种反应具有组织特异性，并且不会扩展到预防其他氧化损伤。冷暴露的早期急性期伴随着氧化还原当量的显著消耗。在这种情况下，由于能量需求增加和ATP消耗增强，ADS是否有能力中和升高的ROS水平是值得怀疑的。长时间暴露于寒冷会导致ADS适应。冬眠动物和耐冻物种在冬眠或冷冻之前会提高其ADS，以便为苏醒做准备并应对苏醒。ROS的参与以及ADS在低温生物中的作用是插入到稳态生理机制中的特征。ADS调节的确切机制尚未完全明确，并且是许多正在进行的有趣科学研究的主题。
