Ischemic preconditioning in the rat hippocampus increases antioxidant activities but does not affect the level of hydroxyl radicals during subsequent severe ischemia

Yun Sik Choi, Kyung Ok Cho, Eun Jeong Kim, Ki Wug Sung, Yun Kim Seong

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

Several studies have demonstrated that ischemic preconditioning increases superoxide dismutase activity, but it is unclear how ischemic preconditioning affects events downstream of hydrogen peroxide production during subsequent severe ischemia and reperfusion in the hippocampus. To answer this question, we investigated whether ischemic preconditioning in the hippocampal CA1 region increases the activities of antioxidant enzymes glutathione peroxidase and catalase, resulting in a decrease in the level of hydroxyl radicals during subsequent severe ischemia-reperfusion. Transient forebrain ischemia was induced by four-vessel occlusion in rats. Ischemic preconditioning for 3 min or a sham operation was performed and a 15-min severe ischemia was induced three days later. Ischemic preconditioning preserved the CA1 hippocampal neurons following severe ischemia. The concentration of 2,3-dihydroxybenzoic acid, an indicator of hydroxyl radical, was measured using in vivo microdialysis technique combined with HPLC. The ischemia-induced increase in the ratio of 2,3-dihydroxybenzoic acid concentration relative to baseline did not differ significantly between preconditioned and control groups. On the other hand, activities of the antioxidant enzymes glutathione peroxidase-1 and catalase were significantly increased at 3 days after ischemic preconditioning in the hippocampus. Our results suggest that, in preconditioned rats, while hydrogen peroxide is generated from severe ischemia, the activity of catalase and glutathione peroxidase-1 is correspondingly increased to eliminate the excessive hydrogen peroxide. However, our results show that the enhanced activity of these antioxidant enzymes in preconditioned rats is not sufficient to decrease hydroxyl radical levels during subsequent severe ischemia-reperfusion.

Original languageEnglish (US)
Pages (from-to)556-563
Number of pages8
JournalExperimental and Molecular Medicine
Volume39
Issue number4
StatePublished - Aug 31 2007

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Ischemic Preconditioning
Hydroxyl Radical
Catalase
Hydrogen Peroxide
Rats
Hippocampus
Ischemia
Antioxidants
Enzymes
Glutathione Peroxidase
Reperfusion
Neurons
Superoxide Dismutase
Hippocampal CA1 Region
Microdialysis
Prosencephalon
2,3-dihydroxybenzoic acid
glutathione peroxidase GPX1
High Pressure Liquid Chromatography
Control Groups

Keywords

  • Brain ischemia
  • Catalase
  • Glutathione peroxidase
  • Hippocampus
  • Hydroxyl radical
  • Ischemic preconditioning

ASJC Scopus subject areas

  • Biochemistry
  • Genetics

Cite this

Ischemic preconditioning in the rat hippocampus increases antioxidant activities but does not affect the level of hydroxyl radicals during subsequent severe ischemia. / Choi, Yun Sik; Cho, Kyung Ok; Kim, Eun Jeong; Sung, Ki Wug; Seong, Yun Kim.

In: Experimental and Molecular Medicine, Vol. 39, No. 4, 31.08.2007, p. 556-563.

Research output: Contribution to journalArticle

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