Polyethylene glycol-conjugated superoxide dismutase fails to blunt postischemic reactive hyperemia

M. A. Helfaer, J. R. Kirsch, S. E. Haun, L. E. Moore, R. J. Traystman

Research output: Contribution to journalArticle

17 Scopus citations

Abstract

We tested the hypothesis that superoxide dismutase (SOD) conjugated with polyethylene glycol (PEG-SOD) would alter hyperemia following complete global cerebral ischemia. Thirty minutes before ischemia pentobarbital-anesthetized piglets were assigned to receive 3 ml of either PEG-SOD (10,000 U/ml; n = 10), an equivalent concentration of PEG (n = 10), or saline (n = 10) in a randomized and blinded manner. Cerebral ischemia was sustained for 10 min by cross-clamping the ascending aorta. Measurements of cerebral blood flow (radiolabeled microspheres) and oxygen consumption were made before ischemia and at 2, 4, 8, 12, and 15 min of reperfusion. Plasma SOD activity was higher in PEG-SOD-treated piglets (134 ± 8 U/ml) than in PEG or saline-treated piglets (<5 U/ml). All groups and all brain regions demonstrated postischemic hyperemia. There were no differences in blood flow between groups at any time point in any region. At 2 min of reperfusion, blood flow to cerebrum rose from 31 ± 4 to 88 ± 9 ml·min-1·100 g-1 (saline), 44 ± 6 to 102 ± 17 ml·min-1·100 g-1 (PEG), and 31 ± 3 to 83 ± 16 ml·ming-1·100 g-1 (PEG-SOD). During reperfusion cerebral oxygen consumption was not different from preischemic values in any group. In conclusion, we demonstrated that exogenously administered PEG-SOD raises serum SOD activity but does not alter the patterns of early cerebral blood flow or metabolic recovery after 10 min of complete global cerebral ischemia in piglets.

Original languageEnglish (US)
Pages (from-to)H548-H553
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume261
Issue number2 30-2
DOIs
StatePublished - Jan 1 1991

Keywords

  • Cerebral blood flow
  • Cerebral ischemia
  • Cerebral metabolism
  • Oxygen-derived free radicals

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

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