Cerebral microvascular changes in permeability and tight junctions induced by hypoxia-reoxygenation

Karen S. Mark, Thomas P. Davis

Research output: Contribution to journalArticle

300 Scopus citations

Abstract

Cerebral microvessel endothelial cells that form the blood-brain barrier (BBB) have tight junctions (TJ) that are critical for maintaining brain homeostasis and low permeability. Both integral (claudin-1 and occludin) and membrane-associated zonula occluden-1 and -2 (ZO-1 and ZO-2) proteins combine to form these TJ complexes that are anchored to the cytoskeletal architecture (actin). Disruptions of the BBB have been attributed to hypoxic conditions that occur with ischemic stroke, pathologies of decreased perfusion, and high-altitude exposure. The effects of hypoxia and posthypoxic reoxygenation in cerebral microvasculature and corresponding cellular mechanisms involved in disrupting the BBB remain unclear. This study examined hypoxia and posthypoxic reoxygenation effects on paracellular permeability and changes in actin and TJ proteins using primary bovine brain microvessel endothelial cells (BBMEC). Hypoxia induced a 2.6-fold increase in [14C]sucrose, a marker of paracellular permeability. This effect was significantly reduced (∼ 58%) with posthypoxic reoxygenation. After hypoxia and posthypoxic reoxygenation, actin expression was increased (1.4- and 2.3-fold, respectively). Whereas little change was observed in TJ protein expression immediately after hypoxia, a twofold increase in expression was seen with posthypoxic reoxygenation. Furthermore, immunofluorescence studies showed alterations in occludin, ZO-1, and ZO-2 protein localization during hypoxia and posthypoxic reoxygenation that correlate with the observed changes in BBMEC permeability. The results of this study show hypoxia-induced changes in paracellular permeability may be due to perturbation of TJ complexes and that posthypoxic reoxygenation reverses these effects.

Original languageEnglish (US)
Pages (from-to)H1485-H1494
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume282
Issue number4 51-4
DOIs
StatePublished - 2002

Keywords

  • Blood-brain barrier
  • Cytoarchitecture
  • Endothelial cells
  • Immunofluorescence

ASJC Scopus subject areas

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

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