An inhibition of ceruloplasmin expression induced by cerebral ischemia in the cortex and hippocampus of rats.

Objective: To explore effects of cerebral ischemia on the ceruloplasmin (Cp) expression in the cortex and hippocampus of rats.

Methods: Male Wistar rats were randomly divided into cerebral ischemia group and control group. Cerebral ischemia was induced by ligating bilateral common carotid arteries and the ischemic rats were further subgrouped according to ischemia time. The control rats received a sham operation. The expression of Cp mRNA in the cortex and hippocampus was measured by reverse transcription polymerase chain reaction (RT-PCR). The Cp expression was shown by immunohistochemistrical (streptavidin peroxidase, SP) method.

Results: In ischemia group, the expression of Cp mRNA in the cortex and hippocampus decreased compared with that in control group (P< 0.01); and the longer rats experienced cerebral ischemia, the lower Cp mRNA expressed. By immunohistochemistry, Cp was shown expressed in the neural cells including epithelial cells of choroid plexus, ependymal cells, astrocytes of cortex and hippocampus, and vascular endothelial cells, but not in pyramidal cells and granulosa cells of cortex and hippocampus. Cp levels in the cortex and hippocampus decreased in rats suffering from cerebral ischemia for 3 d, 7 d and 28 d but not in rats exposed to ischemia for 1 d compared with that in control group (P< 0.05). Iron concentration correlated negatively with Cp expression in the cortex and hippocampus of rats exposure to ischemia (the cortex, r = -0.831, P< 0.01; the hippocampus, r = -0.809, P< 0.01).

Conclusion: Cerebral ischemia inhibited Cp expression in the cortex and hippocampus of rats. The decrease of Cp might be involved in iron deposition in neurons.