Ischemic Neuronal Injury and Gene Expression of Facilitative and Inhibitory Growth Factors

We studied the regulatory mechanism of gene expression for the facilitative growth factor, basic fibroblast growth factor (bFGF), and the growth inhibitory factor (GIF) in ischemic brain tissue. The mRNA expression of these growth factors was studied using the in situ hybridization method and compared with the expression of c-fos, c-jun, and heat shock protein(HSP) 70 mRNA in the serial sections of the brain tissue during the recirculation period after 2 h-occlusion of the middle cerebral artery in rat. The pattern of gene expression for bFGF, c-fos, and c-jun is quite similar, whereas HSP70 and GIF gene expression is somewhat different from others. The result of these findings suggests that gene expression of facilitative and inhibitory growth factors is well controlled in order. In the same tissue preparation, we studied gene expression of neuropsin, a hippocampus-specific serine protease. Down-regulation of neuropsin after ischemic insult was found and it may be related to the restorative process of hippocampal neurons against ischemic stress.