Time-dependent changes in superoxide dismutase, catalase, xanthine dehydrogenase and oxidase activities in focal cerebral ischaemia

Cytobios. 2000;102(401):157-72.

Abstract

Time-dependent changes in the activities of antioxidant enzymes and an oxidant enzyme, xanthine oxidase (XO), were detected in primary and peri-ischaemic brain regions during permanent occlusion of the middle cerebral artery (MCAO) in rats. There were no changes in superoxide dismutase (SOD) and catalase (CAT) activities after 3 h of MCAO, whereas antioxidant enzyme activities decreased significantly in ischaemic brain areas following 24 h of ischaemia. After 48 h, the enzyme activities returned to the baseline but then a further increase was observed in ischaemic brain areas by 72 h post-ischaemia. Normally, XO exists as a dehydrogenase (XD), but it is converted to XO which contributes to injury in some ischaemic tissues. The XO activity increased slightly at 3 h after ischaemia, but after 24 h of ischaemia it returned to the baseline and then remained relatively unchanged in ischaemic areas. Pretreatment with allopurinol before ischaemia prevented changes in SOD and CAT activities and attenuated brain oedema during 24 h of ischaemia. Neither XO nor XD activity changed in allopurinol-treated rats at the times of ischaemia. These results indicated that ischaemic brain tissue remained vulnerable to free radical damage for as long as 48 h after ischaemia, and XO was probably not an important source of free radicals in cerebral ischaemia.

Publication types

  • Comparative Study

MeSH terms

  • Allopurinol / pharmacology
  • Animals
  • Blood Gas Analysis
  • Blood Pressure
  • Brain Edema / drug therapy
  • Brain Edema / etiology
  • Brain Ischemia / drug therapy*
  • Brain Ischemia / enzymology*
  • Catalase / drug effects
  • Catalase / metabolism
  • Enzyme Inhibitors / pharmacology
  • Lipid Peroxidation / drug effects
  • Male
  • Oxidoreductases / drug effects
  • Oxidoreductases / metabolism*
  • Rats
  • Rats, Sprague-Dawley
  • Superoxide Dismutase / drug effects
  • Superoxide Dismutase / metabolism
  • Time Factors
  • Xanthine Dehydrogenase / drug effects
  • Xanthine Dehydrogenase / metabolism
  • Xanthine Oxidase / antagonists & inhibitors
  • Xanthine Oxidase / metabolism

Substances

  • Enzyme Inhibitors
  • Allopurinol
  • Oxidoreductases
  • Catalase
  • Superoxide Dismutase
  • Xanthine Dehydrogenase
  • Xanthine Oxidase