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

通过与温度无关的能量代谢相关物质测量研究冬眠主要器官的抗氧化机制

基本信息

批准号：
16390057
负责人：
HASHIMOTO Masaaki
金额：
$ 9.54万
依托单位：
Asahikawa Medical College
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2005
项目状态：
已结题

项目摘要

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)

在从冬眠中醒来时，体温比冰冻环境高1℃左右的小型哺乳动物，在几个小时内体温会上升30℃以上。由于当时能量代谢的强烈增加，主要器官如大脑和心脏被认为暴露于强烈的氧化应激。然而，冬眠者被认为具有抗氧化机制，因为它们在整个冬眠期间没有表现出任何病理学。本研究以叙利亚仓鼠为研究对象，探讨了其冬眠唤醒和抗氧化应激的机制，获得了以下结果：1.在深冬眠过程中，体内没有蛋白质和mRNA的重新合成，即基因的转录和翻译停止。在冬眠的唤醒阶段，基因表达重新开始，伴随着能量代谢的增加。（Jpn.J.Physiol，2004，54）2.一旦从冬眠开始唤醒，由于尾侧体中脉管系统的交感神经活动的增加，分配到尾侧体的血液暂时移动到吻侧，这导致分配到大脑的血液增加。（Am.J.Physiol.2005）3.在觉醒阶段，大脑细胞外液（ECF）中的尿酸（氧化应激的指标）暂时增加。抗坏血酸是一种水溶性抗氧化剂，在深度冬眠期间，大脑ECF中的抗坏血酸水平会增加，随着唤醒阶段的推进，抗坏血酸水平会降低。ECF谷胱甘肽（GSH）的变化就像冬眠期间抗坏血酸变化的镜像。脑组织中的抗坏血酸和谷胱甘肽没有变化，但尿酸随着冬眠的觉醒而增加。（Behav.Brain Res，2006年）