Generalized induction of 72-kDa heat-shock protein after transient focal ischemia in rat brain

The time course of 72-kDa heat-shock protein (hsp72) induction was evaluate d by immunoblotting in cerebral cortex, striatum, hippocampus, cerebellum, liver, and kidney of rats subjected to 60-min focal cerebral ischemia follo wing proximal unilateral occlusion of the right middle cerebral artery (MCA ). Neurological examinations indicated that maximum deficits in reflex and sensorimotor functions occurred 24-48 h after reperfusion (40% lower than b aseline), while significant recovery occurred at 72 h (33% higher than 48 h ). hsp72 was present in all tissues at 6 h. The regions perfused by the occ luded MCA showed a higher induction than the corresponding contralateral on es, hsp72 reached its maximum level in ipsilateral cerebral cortex and stri atum at 24 h, whereas in the contralateral cortex and cerebellum the protei n reached its maximum expression at 48 h, that is 24 h before functional re covery. This delay suggests a role of the protein in plastic events sustain ing neurological recovery.