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 exis ts in the literature as to whether they protect or injure neurons in t his setting. Methods: Astrocytes in the rat hippocampus were disabled with stereotactic administration of a gliotoxin, ethidium bromide, 3 d ays prior to induction of forebrain ischemia. The extent of neuronal i njury in this group was compared to a control category receiving intra hippocampal 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) o r ethidium bromide-treated animals (P < 0.05). Conclusions: The result s suggest that activated astrocytes are protective to neurons subjecte d to an ischemic insult. This may result from their ability to elabora te neurotrophic factors, buffer potassium and metabolize a variety of neurotransmitters.