Induction of suppressor of cytokine signaling-3 in astrocytes of the rat hippocampus following transient forebrain ischemia

We investigated the spatiotemporal expression of suppressor of cytokine signaling-3 (SOCS-3) in the rat hippocampus following transient forebrain ischemia using in situ hybridization and reverse transcriptase-polymerase chain reaction (RT-PCR) analysis. Messenger RNA for SOCS-3 was constitutively expressed in neurons of the pyramidal cell and granule cell layers in control animals; however, significant induction was detected in reactive astrocytes preferentially located in the CA1 and the dentate hilar regions of the ischemic hippocampus. SOCS-3 mRNA was induced within 3 days of ischemia and maintained for more than 2 weeks. The in situ hybridization data agreed with the semiquantitative RT-PCR analysis. These results demonstrate SOCS-3 induction occurs in reactive astrocytes of the post-ischemic hippocampus, suggesting that SOCS-3 is involved in regulating the astroglial reaction to an ischemic insult.