Role of superoxide in poly(ADP-ribose) polymerase upregulation after transient cerebral ischemia

Purnima Narasimhan, Miki Fujimura, Nobuo Noshita, Pak H. Chan

Research output: Contribution to journalArticlepeer-review

34 Citations (Scopus)


Oxidative stress plays a pivotal role in ischemic-reperfusion cell injury. Oxygen-derived free radicals trigger DNA strand damage, which is responsible for the activation of poly(ADP-ribose) polymerase (PARP). Recent studies have shown that peroxynitrite is the primary mediator of DNA damage and, hence, PARP activation after ischemia. PARP activation depletes NAD and ATP pools, ultimately resulting in necrotic cell death by loss of energy stores. Our study shows that PARP is upregulated as early as 15 min after 1 h of transient focal cerebral ischemia and remains for 8 h. We also examined the role of superoxide in PARP induction using copper/zinc-superoxide dismutase transgenic mice. Immunohistochemical and Western blotting data showed that there was no increased induction in PARP expression in these mice, suggesting that one of the mechanisms by which ischemic injury is attenuated in these mice might be by the inhibition of PARP induction. Furthermore, double staining of ischemic tissue with a PARP antibody and terminal deoxynucleotidyl transferase-mediated uridine 5′-triphosphate-biotin nick end labeling (TUNEL) indicated that most cells that are positive for TUNEL do not stain for the PARP antibody, confirming recent reports that PARP activation is involved in necrotic cell death rather than apoptosis during ischemic-reperfusion injury.

Original languageEnglish
Pages (from-to)28-36
Number of pages9
JournalMolecular Brain Research
Issue number1-2
Publication statusPublished - 2003 May 12
Externally publishedYes


  • Cell death
  • Cerebral ischemia
  • Cytochrome c
  • Poly(ADP-ribose) polymerase induction
  • SOD1
  • Superoxide

ASJC Scopus subject areas

  • Molecular Biology
  • Cellular and Molecular Neuroscience


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