Role of the antioxidant ascorbate in hibernation and warming from hibernation
Role of the antioxidant ascorbate in hibernation and warming from hibernation
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DOI：
10.1016/s1532-0456(02)00118-7
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发表时间：
2002-12-01
影响因子：
3.9
通讯作者：
Rice, ME
中科院分区：
文献类型：
--
作者：
Drew, KL;Toien, O;Rice, ME
地松鼠在冬眠期间可以忍受高达90%的脑血流量减少，以及在从麻木中周期性唤醒时的快速再灌注，而没有明显的神经损伤。因此，冬眠被研究为对脑缺血和其他类型的脑损伤的耐受性的模型。代谢抑制可能起着主要的适应作用，使冬眠物种能够忍受血液流量的剧烈波动。冬眠生理学的其他几个方面也与对缺血和再灌注的耐受性一致，这表明多种神经保护性适应可能在冬眠期间协同工作。目前的工作的目的是审查证据增强抗氧化防御系统在冬眠期间，重点抗坏血酸，并讨论这些抗氧化剂在冬眠期间的潜在作用。与血流量、营养和氧气输送的急剧减少相一致，抗氧化剂抗坏血酸[（Asc）p]的血浆浓度在冬眠期间增加1-5倍。相反，在复温期间，[Asc]p以相对较快的速率下降，在最大O-2消耗时达到峰值。O-2消耗的这一峰值也与血浆尿酸盐浓度的短暂上升相一致，这与活性氧产生的激增相一致。总体而言，数据表明，血浆抗坏血酸浓度升高，准备分配到代谢活跃的组织在激增的氧化代谢过程中，伴随着复温在冬眠。这种抗坏血酸盐池，以及其他抗氧化防御系统的表达增加，可以保护脆弱的组织在冬眠和冬眠后的复温期间免受氧化应激。更好地了解抗坏血酸在冬眠中的作用可能会指导抗坏血酸和其他抗氧化剂在治疗中风，头部创伤和神经退行性疾病中的使用。(C)2002年爱思唯尔科技有限公司All rights reserved.
Ground squirrels tolerate up to 90% reductions in cerebral blood flow during hibernation as well as rapid reperfusion upon periodic arousal from torpor without apparent neurological damage. Thus, hibernation is studied as a model of tolerance to cerebral ischemia and other types of brain injury. Metabolic suppression likely plays a primary adaptive role that allows hibernating species to tolerate dramatic fluctuations in blood flow. Several other aspects of hibernation physiology are also consistent with tolerance to ischemia and reperfusion suggesting that multiple neuroprotective adaptations may work in concert during hibernation. The purpose of the present work is to review evidence for enhanced antioxidant defense systems during hibernation, with a focus on ascorbate, and discuss potential roles of these antioxidants during hibernation. In concert with dramatic decreases in blood flow, nutrient and oxygen delivery, plasma concentrations of the antioxidant ascorbate [(Asc)p] increase 1-5-fold during hibernation. In contrast, during re-warming, [Asc]p declines at a relatively rapid rate that peaks at the time of maximal O-2 consumption. This peak in O-2 consumption also coincides with a brief rise in plasma urate concentration consistent with a surge in reactive oxygen species production. Overall, data suggest that elevated concentration of plasma ascorbate is poised for distribution to metabolically active tissues during the surge in oxidative metabolism that accompanies re-warming during hibernation. This pool of ascorbate, as well as increased expression of other antioxidant defense systems, may protect vulnerable tissues from oxidative stress during hibernation and re-warming from hibernation. Better understanding of the role of ascorbate in hibernation may guide use of ascorbate and other antioxidants in treatment of stroke, head trauma and neurodegenerative disease. (C) 2002 Elsevier Science Inc. All rights reserved.