An investigation of anti-oxidation mechanism in hibernator major organs by means of temperature-independent measurement of the substances related to energy metabolism

在从冬眠中唤醒时，体温比冰冻环境高出约1℃的小哺乳动物在几个小时内表现出30℃以上的温升。由于当时能量代谢的剧烈增加，大脑和心脏等主要器官被认为暴露在强烈的氧化应激下。然而，冬眠者被认为配备了抗氧化机制，因为它们在整个冬眠期不会表现出任何病理。在本研究中，我们对叙利亚仓鼠从冬眠中唤醒和抗氧化应激的潜在机制进行了研究，目前已获得以下结果：1.在深度冬眠中，蛋白质和mRNA没有从头合成，即任何基因的转录和翻译都停止在体内。在冬眠的觉醒阶段，伴随着能量代谢的增加，基因表达重新开始。(Jpn.J.Physiol，2004，54)2.一旦从冬眠中唤醒，由于尾体血管的交感神经活动增加，分配到尾半身的血液暂时移动到吻侧，导致向大脑的血液分配增加。(AM.J.Physiol.2005)3.大脑细胞外液(ECF)中的尿酸在觉醒阶段暂时增加，这是氧化应激的一个指标。在深度冬眠期间，大脑中抗坏血酸的ECF水平会增加，这是一种水溶性抗氧化剂，随着觉醒阶段的推进而降低。ECF谷胱甘肽(GSH)的变化与冬眠期间抗坏血酸的变化如出一辙。脑组织中的抗坏血酸和谷胱甘肽没有变化，但尿酸随着冬眠的进展而增加。(Behav.Brain Res，2006)

During arousal from hibernation, small mammal whose body temperature is by about 1℃ higher than the freezing environment shows the temperature rise of more than 30℃ in several hours. Because of the intense increases in the energy metabolism at that time, the major organs such as the brain and heart are thought to be exposed to a strong oxidation stress. Hibernators are, however, assumed to be equipped with anti-oxidation mechanism since they do not show any pathology throughout the hibernation period. In this study, we investigated the underlying mechanism of arousal from hibernation and of anti oxidation stress in Syrian hamsters, and the following results have been acquired so far.1.During deep hibernation, there is no de-novo synthesis of protein and mRNA, namely any transcription and translation of the gene stop in the body. The gene expression is restarted accompanying to an increase in the energy metabolism in the arousal phase of hibernation. (Jpn.J.Physiol,2004,54)2.Once arousal from hibernation begins, the blood distributed to caudal half of the body temporarily moves to rostral side owing to an increase in the sympathetic nerves activities of the vasculature in the caudal body, which results in the increase of blood distribution to the brain. (Am.J.Physiol.2005)3.Uric acid, an index of oxidation stress, in the extra cellular fluid (ECF) of the brain increased temporarily in the arousal phase. The brain ECF level of ascorbic acid, a water soluble antioxidants, increases during deep hibernation, which reduces as the arousal phase advances. ECF glutathione (GSH) changes like a mirror image of the change of ascorbic acid during hibernation. Brain tissue ascorbic acid and GSH does not change, but uric acid increases as arousal from hibernation advances. (Behav.Brain Res,2006)