Proprotein convertase 1 mRNA and protein expression in ischemic rat cortex after reperfusion

Proprotein convertase 1 (PC1) is a member of the family of proprotein convertases (PCs), which are the processing enzymes of neuropeptides. Previous studies have addressed PC1 effects with regard to the neuroendocrine system. In this study, the developing changes of PC1 mRNA and PC1 protein in rat cortices after transient focal cerebral ischemia were investigated by fluorescent double labeling (both in situ hybridization and immunocytochemistry) using a transient focal cerebral ischemia model in rats. The results were compared with those of sham-operated rat cortices. Both the mRNA and protein levels of PC1 in ischemic cortices decreased gradually at 4, 8, and 16 hours of reperfusion after 100 minutes of middle cerebral artery occlusion. After 24 hours of reperfusion, enhanced intensities of signals for PC1 protein were observed, while signals for PC1 mRNA remained low. These results suggest that transient focal cerebral ischemia influences PC1 mRNA and protein expression in cortices of ischemic rats. Thus, PC1 is regulated by ischemic stress.