Temporal Profiles of Stress Protein Inductions after Focal Transient Ischemia in Mice Brain

Background Stress proteins have been found to play important protective roles against ischemic brain injury under hypoxic, oxidative, heat shock, and proteasome stresses. Methods In the present study, we investigated the temporal profiles of the major stress proteins including hypoxia-inducible factor-1α (HIF-1α), glutathione (GSH), heat shock protein 72 (HSP72), constitutive heat shock cognate protein 73 (HSC73), and ubiquitin after 45 minutes of transient middle cerebral artery occlusion (tMCAO) in the mice brain up to 7 days after reperfusion. Results Immunohistochemical analyses of HIF-1α, GSH, HSP72, and ubiquitin showed little immunoreactivity of neural cells in sham control brain, whereas HSC73 showed a constitutive immunoreactivity. After tMCAO, HSC73 showed the fastest increase at 12 hours in the peri-ischemic area, followed by HIF-1α with a peak at 24 hours, GSH, HSP72, and ubiquitin with a peak at 72 hours. All these stress proteins returned toward the baseline levels until 7 days. In the ischemic core, these stress proteins showed a similar change with less reaction compared to the peri-ischemic area. Conclusions These data showed temporal expressions of HIF-1α, GSH, HSP72, HSC73, and ubiquitin in the mice brain after tMCAO, which might provide a better understanding of neuroprotective mechanisms and novel targets for therapeutic intervention of brain ischemic disease.