Intracerebral injection of autologous whole blood in rats: time course of inflammation and cell death

Intracerebral hemorrhage is associated with stroke and head trauma. The pur pose of this study was to study brain inflammation and cell death in adult rats 1 h to 4 weeks after injection of blood into the striatum. Terminal dU TP nick-end-labeling positive dying cells were evident 4 h to 4 weeks post- hemorrhage. Neutrophil infiltration was brief and peaked at 48 h. CD8a immu noreactive Lymphocytes, possibly natural killer cells, became apparent at 4 8 h and persisted for 1 week. Microglial reaction was evident at 4 h and pe rsisted for 4 weeks. We conclude that extravascular blood causes a mixed in flammatory cell reaction in brains that is maximal from 48-72 h following h emorrhage. This is associated with death of brain cells over a prolonged pe riod of at least 4 weeks. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.