Reduction of apurinic/apyrimidinic endonuclease expression after transient global cerebral ischemia in rats: Implication of the failure of DNA repair in neuronal apoptosis

Makoto Kawase, Miki Fujimura, Yuiko Monta-Fujimura, Pak H. Chan

Research output: Contribution to journalArticlepeer-review

85 Citations (Scopus)

Abstract

Background and Purpose - To clarify the relationship between apurinic/apyrimidinic endonuclease (APE/Ref-1), a multifunctional protein in the DNA base excision repair pathway, and delayed neuronal cell death associated with apoptosis, we examined the expression of APE/Ref-1 before and after transient global ischemia in rats. Methods - Global ischemia was induced by bilateral common carotid artery occlusion and hypotension. Expression of the APE/Ref-1 protein was evaluated by Western blot and immunohistochemical analyses. Apoptosis after global ischemia was observed by DNA electrophoresis and terminal deoxynucleotidyl transferase-mediated uridine 5'-triphosphate-biotin nick end labeling (TUNEL) staining. Results - Immunohistochemistry showed the nuclear expression of APE/Ref-1 in the control brains. Nuclear immunoreactivity of APE/Ref-1 was significantly decreased 2 days after 10 minutes of ischemia in the hippocampal CA1 subregion. Western blot analysis of a sample from the normal brains showed a characteristic 37-kDa band, which was reduced in the hippocampal CA1 subregion after ischemia. A significant amount of DNA fragmentation was observed at 3 days but not at 1 day after ischemia. Double staining with APE/Ref-1 and TUNEL clearly showed that the neurons that lost APE/Ref-1 immunoreactivity became TUNEL positive. Conclusions - Our data provide evidence that APE/Ref-1 decreased in hippocampal CA1 neurons after transient global ischemia and that this reduction precedes DNA fragmentation, which is destined to cause apoptosis. Our results suggest the possibility that a decrease of APE/Ref-1 activity and the failure of DNA repair may underlie the mechanism of apoptosis after transient focal ischemia.

Original languageEnglish
Pages (from-to)441-449
Number of pages9
JournalStroke
Volume30
Issue number2
DOIs
Publication statusPublished - 1999 Feb

Keywords

  • Apoptosis
  • Cerebral ischemia
  • DNA base excision repair
  • Rats
  • Transient

ASJC Scopus subject areas

  • Clinical Neurology
  • Cardiology and Cardiovascular Medicine
  • Advanced and Specialised Nursing

Fingerprint Dive into the research topics of 'Reduction of apurinic/apyrimidinic endonuclease expression after transient global cerebral ischemia in rats: Implication of the failure of DNA repair in neuronal apoptosis'. Together they form a unique fingerprint.

Cite this