Heat shock proteins (HSPs) 60 and 10 are stress-inducible mitochondrial matrix 
proteins that form a chaperonin complex that is important for mitochondrial 
protein folding and function. The effect of cerebral ischemia on mitochondrial 
HSPs is unclear. The topographical and chronological patterns of HSP60 and HSP10 
messenger ribonucleic acid (mRNA) expression and induction were investigated in 
the rat focal cerebral ischemia model. Focal cerebral ischemia was produced by 
transient middle cerebral artery occlusion for 30 or 90 min. Expression of mRNAs 
was analyzed using reverse transcription-polymerase chain reaction (RT-PCR) and 
in situ hybridization. RT-PCR analysis showed that both HSP60 and HSP10 mRNA 
levels increased significantly in the ischemic cortex from 4 to 24 h of 
reperfusion after 30 min of occlusion. In situ hybridization analysis 
demonstrated significant induction of both mRNAs in the whole ischemic cortex 
after 30 min of occlusion and in the dorsomedial border (penumbra) of the 
ischemic cortex and ipsilateral hippocampus after 90 min of occlusion. 
Expression patterns and the timing of the induction of both HSP60 and HSP10 
mRNAs were identical throughout the experiments. Simultaneous induction of the 
mRNAs for the mitochondrial chaperonins, HSP60 and HSP10, in various regions in 
focal cerebral ischemia demonstrates that mitochondrial stress conditions 
persist concomitantly with cytosolic stress conditions in focal cerebral 
ischemia.