EARLY 72-KDA HEAT-SHOCK PROTEIN INDUCTION IN MICROGLIAL CELLS FOLLOWING FOCAL ISCHEMIA IN THE RAT-BRAIN

Focal cerebral ischemia in the adult rat produces induction of 72-kDa heat shock protein (HSP-72) in neurons, glia and endothelial cells. Do uble antigen immunocytochemistry was carried out to find out whether m icroglial cells express HSP-72 following 1-h middle cerebral artery (M CA) occlusion. A monoclonal antibody against the CR3 complement recept or (OX-42) specific for microglia was used followed by a monoclonal an tibody against HSP-72, Go-localization of these antibodies was seen in cells of the ipsilateral corpus callosum and striatum at 3 h followin g l-h MCA occlusion, and in the ipsilateral striatal penumbra, corpus callosum and cortex at 8 h. Results demonstrate that stellate microgli al cells show an early response to 1-h MCA occlusion by expressing ind ucible HSP-72, thus suggesting that microglial cells are sensitive to the ischemic insult.