The nature of antioxidant defense mechanisms: a lesson from transgenic studies. [1998](IR91)
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(Memo Item created on December 17, 2011 01:41 PM)
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The nature of antioxidant defense mechanisms: a lesson from transgenic studies.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1533365/
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Environ Health Perspect. 1998 October; 106(Suppl 5): 1219–1228.
PMCID: PMC1533365
Copyright notice
Research Article
The nature of antioxidant defense mechanisms: a lesson from transgenic studies.
Y S Ho, J L Magnenat, M Gargano, and J Cao
Institute of Chemical Toxicology, Wayne State University, Detroit, MI 48201, USA. yho@wayne.edu
Abstract
Reactive oxygen species (ROS) have been implicated in the pathogenesis of many clinical disorders such as adult respiratory distress syndrome, ischemia-reperfusion injury, atherosclerosis, neurodegenerative diseases, and cancer. Genetically engineered animal models have been used as a tool for understanding the function of various antioxidant enzymes in cellular defense mechanisms against various types of oxidant tissue injury. Transgenic mice overexpressing three isoforms of superoxide dismutase, catalase, and the cellular glutathione peroxidase (GSHPx-1) in various tissues show an increased tolerance to ischemia-reperfusion heart and brain injury, hyperoxia, cold-induced brain edema, adriamycin, and paraquat toxicity. These results have provided for the first time direct evidence demonstrating the importance of each of these antioxidant enzymes in protecting the animals against the injury resulting from these insults, as well as the effect of an enhanced level of antioxidant in ameliorating the oxidant tissue injury. To evaluate further the nature of these enzymes in antioxidant defense, gene knockout mice deficient in copper-zinc superoxide dismutase (CuZnSOD) and GSHPx-1 have also been generated in our laboratory. These mice developed normally and showed no marked pathologic changes under normal physiologic conditions. In addition, a deficiency in these genes had no effects on animal survival under hyperoxida. However, these knockout mice exhibited a pronounced susceptibility to paraquat toxicity and myocardial ischemia-reperfusion injury. Furthermore, female mice lacking CuZnSOD also displayed a marked increase in postimplantation embryonic lethality. These animals should provide a useful model for uncovering the identity of ROS that participate in the pathogenesis of various clinical disorders and for defining the role of each antioxidant enzyme in cellular defense against oxidant-mediated tissue injury.
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(Memo Item created on December 17, 2011 01:47 PM)
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English to Chinese translation of some medical terms relevant to this paper
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ischemia-reperfusion injury
ischemia
【醫學】局部缺血
reperfusion
再灌注
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