Characterization of monocyte chemoattractant protein-1 expression following a kainate model of status epilepticus

Brain injury due to seizure induces a robust inflammatory response that involves multiple factors. Although the expression of chemokines has been identified as a part of this response, there are remaining questions about their relative contribution to seizure pathogenesis. To address this, we report the expression profile of the chemokine, monocyte chemoattractant protein-1 (MCP-1, CCL2), during kainate-induced seizure in the rat hippocampus. Furthermore, we compare MCP-1 expression to the temporal profile of blood-brain barrier (BBB) permeability and immune cell recruitment at the injury site, since both of these events have been linked to MCP-1. We find that BBB permeability increased prior to upregulation of MCP-1, while MCP-1 upregulation and immune cell recruitment occurred concurrently, 7-13 h after opening of the BBB. Our findings support the following conclusions: (1) BBB opening to large proteins does not require MCP-1 upregulation; (2) Leukocyte immigration is not sufficient to induce BBB opening to large proteins; (3) MCP-1 upregulation likely mediates recruitment of macrophages/microglia and granulocytes during seizure injury, thus warranting further investigation of this chemokine.