Neuroprotective role of astrocytic gap junctions in ischemic stroke

Cell Commun Adhes. 2003 Jul-Dec;10(4-6):413-7. doi: 10.1080/cac.10.4-6.413.417.

Abstract

The role of astrocytic gap junctions in ischemia remains controversial. Several studies support that astrocytic gap junctions play a role in the spread of hypoxic injury, while other reports have demonstrated that blocking astrocytic gap junctions increases neuronal death. Using a stroke model on animals in which the astrocytic gap junction protein connexin43 (Cx43) was compromised, we explored the neuroprotective role of astrocytic gap junctions. A focal brain stroke was performed on heterozygous Cx43 null [Cx43(+/-)] mice, wild type [Cx43(+/+)] mice, astrocyte-directed Cx43 deficient [Cx43(fl/ fl)/hGFAP-cre] mice (here designated as Cre(+) mice), and their corresponding controls [Cx43(fl/fl)] (here designated as Cre(-) mice). Four days following stroke, ischemic lesions were measured for size and analyzed immunohistochemically. Stroke volume was significantly larger in Cx43(+/-) and Cre(+) mice compared to Cx43(+/+) and Cre(-) mice, respectively. Apoptosis as detected by TUNEL labeling and caspase-3 immunostaining was amplified in Cx43(+/-) and Cre(+) mice compared to their control groups. Furthermore, increased inflammation as characterized by the immunohistochemical staining of the microglial marker CD11b was observed in the Cre(+) mice penumbra. Astrocytic gap junctions may reduce apoptosis and inflammation in the penumbra following ischemic insult, suggesting that coupled astrocytes fulfill a neuroprotective role under ischemic stroke conditions.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis / genetics
  • Apoptosis / physiology*
  • Astrocytes / cytology*
  • Astrocytes / metabolism
  • Brain Ischemia / metabolism
  • Brain Ischemia / pathology
  • CD11 Antigens / immunology
  • Cell Communication / physiology*
  • Connexin 43 / genetics
  • Connexin 43 / metabolism*
  • Gap Junctions / metabolism*
  • Mice
  • Mice, Knockout
  • Mice, Transgenic
  • Models, Animal
  • Stroke / metabolism*
  • Stroke / pathology

Substances

  • CD11 Antigens
  • Connexin 43