Ischemic neuronal injury is ameliorated by astrocyte activation.
BACKGROUND
The motivation of this study was to more precisely define the in vivo role of astrocytes in forebrain ischemia. Controversy exists in the literature as to whether they protect or injure neurons in this setting.


METHODS
Astrocytes in the rat hippocampus were disabled with stereotactic administration of a gliotoxin, ethidium bromide, 3 days prior to induction of forebrain ischemia. The extent of neuronal injury in this group was compared to a control category receiving intrahippocampal saline only.


RESULTS
Saline-injected animals demonstrated decreased hippocampal CA1 sector injury, and increased gliosis on the side of the injection compared to the contralateral side (P < 0.01) or ethidium bromide-treated animals (P < 0.05).


CONCLUSIONS
The results suggest that activated astrocytes are protective to neurons subjected to an ischemic insult. This may result from their ability to elaborate neurotrophic factors, buffer potassium and metabolize a variety of neurotransmitters.
Louw
D F
DF
Department of Clinical Neurosciences, University of Calgary, Canada.
Masada
T
T
Sutherland
G R
GR
D000818:Animals; D001253:Astrocytes / Q000737:chemistry / Q000166:cytology* / Q000187:drug effects; D002450:Cell Communication / Q000502:physiology; D016923:Cell Death / Q000187:drug effects; D002540:Cerebral Cortex / Q000098:blood supply / Q000166:cytology; D003342:Corpus Striatum / Q000098:blood supply / Q000166:cytology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004996:Ethidium / Q000494:pharmacology; D005904:Glial Fibrillary Acidic Protein / Q000032:analysis / Q000378:metabolism; D006624:Hippocampus / Q000098:blood supply / Q000166:cytology; D002546:Ischemic Attack, Transient / Q000503:physiopathology*; D008297:Male; D009474:Neurons / Q000166:cytology*; D019384:Nucleic Acid Synthesis Inhibitors / Q000494:pharmacology; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley
D004791:Enzyme Inhibitors; D005904:Glial Fibrillary Acidic Protein; D019384:Nucleic Acid Synthesis Inhibitors; D011500:Protein Synthesis Inhibitors; D004996:Ethidium