Temporal Profile of Cells with Proteolipid Protein mRNA Signals in the Hippocampus after Transient Global Ischemia

The vulnerability of oligodendrocytes after cerebral ischemia still remains unclear. The purpose of this study was to clarify the response of oligodendrocytes in the hippocampus after transient global ischemia. Bilateral common carotid artery BCCA occlusion for 5 min was carried out in gerbils and brain sections obtained from gerbils 4 days, 2 weeks and 2 months after BCCA occlusion were used to study the response of oligodendrocytes and astrocytes by using in situ hybridization histochemistry for proteolipid protein PLP mRNA and immunohistochemistry for glial fibrillary acidic protein GFAP , respectively. BCCA occlusion for 5 min caused delayed neuronal death in the CA1 sector of the hippocampus. The number of PLP mRNApositive cells increased transiently in the CA1 CA3 sectors and corpus callosum from 4 days to 2 weeks, but returned to the control level two months later in both sectors. The response of PLP mRNA-positive cells after transient global ischemia was very similar to that of isotropic reactive astrocytes. Our results suggest that oligodendrocytes in the hippocampus may be as resistant as astrocytes against transient global ischemia. Cerebral Blood Flow and Metabolism 18 1 6, 2006 oligodendrocyte, ischemia, hippocampus, proteolipid protein, gliosis Division of Strokology, Department of Cardiovascular Medicine, Osaka University Graduate School of Medicine 2 2 Yamadaoka, Suita-city, Osaka 565 0871 Japan Department of Clinical Neuroscience, Hiroshima Graduate School of Biomedical Sciences