Induction of macrophage inflammatory protein MIP-1α mRNA on glial cells after focal cerebral ischemia in the rat

Abstract The distribution and cell source of macrophage inflammatory protein-1 α (MIP-1 α ) mRNA induced by transient and permanent middle cerebral artery occlusion (MCAO) were investigated by a double in situ hybridization technique. The distribution and time course of the induction of MIP-1 α mRNA were similar in the two MCAO models. MIP-1 α mRNA was not detected in the sham-operated rat brain. MIP-1 α mRNA was induced by MCAO with the peak of expression at 4–6 h after the onset of occlusion, and the signals of MIP-1 α mRNA were observed in the ischemic core region at an earlier time point, and thereafter intensely in the penumbra of the ischemic area. The signals of MIP-1 α mRNA were evident on Mac-1 α mRNA-positive cells, but not on glial fibrillary acidic protein (GFAP) mRNA-positive cells, indicating that MIP-1 α mRNA was induced in microglia/macrophages of the rat brain after focal cerebral ischemia.