Acute effects of 17β-estradiol on oxidative stress in ischemic rat striatum

Norikatsu Kii, Naoto Adachi, Keyue Liu, Tatsuru Arai

Research output: Contribution to journalArticle

20 Citations (Scopus)

Abstract

Changes in the extracellular concentrations of monoamines, their metabolites, and hydrogen peroxide in the rat striatum during middle cerebral artery (MCA) occlusion and reperfusion were investigated by a microdialysis procedure, and the effects of 17β-estradiol and tamoxifen (an antagonist of estrogen receptors) on them were evaluated. Male Wistar rats were randomly divided into four groups: saline-treated animals, 17β-estradiol-treated animals, saline-plus-tamoxifen-treated animals, and 17β-estradiol-plus- tamoxifen-treated animals. Sixty minutes after an intracerebroventricular injection of saline (20 μL) or 17β-estradiol (150 μg/20 μL), all animals were subjected to 15-minute MCA occlusion under anesthesia. Tamoxifen (1.5 mg) or vehicle was intravenously administered 30 minutes before the saline or 17β-estradiol treatment. Microdialysis samples in the striatum were collected every 15 minutes, and concentrations of monoamines, their metabolites, and hydrogen peroxide were determined. Delayed neuronal death in the striatal neurons was observed after 7 days by light microscopy. Administration of 17β-estradiol reduced neuronal damage caused by focal ischemia. Tamoxifen did not affect the improvement by 17β-estradiol. Although transient ischemia produced a marked increase in the dopamine level, there were no differences in the peak level among the groups. The level of hydrogen peroxide was increased after reperfusion in the saline group. The level in the 17β-estradiol group was suppressed before induction of ischemia, and no increase was observed by ischemia. Tamoxifen did not affect the suppression of the increase by 17β-estradiol. Acute treatment with 17β-estradiol showed a protective effect against ischemia-reperfusion injury. Antioxidant effects of the agent may be a predominant mechanism underlying the protection.

Original languageEnglish
Pages (from-to)27-32
Number of pages6
JournalJournal of Neurosurgical Anesthesiology
Volume17
Issue number1
Publication statusPublished - Jan 1 2005
Externally publishedYes

Keywords

  • 17β-estradiol
  • Delayed neuronal death
  • Dopamine
  • Hydrogen peroxide
  • Middle cerebral artery
  • Striatum

ASJC Scopus subject areas

  • Surgery
  • Clinical Neurology
  • Anesthesiology and Pain Medicine

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