Establishment and characterization of spinal cord microvascular endothelial cell lines

Abstract

Abstract Objectives The blood–spinal cord barrier ( BSCB ) has been recognized as one of the barrier organs in the central nervous system. Unlike the blood–brain barrier ( BBB ), the function of the BSCB still remains to be fully understood, partly because of the lack of a good in vitro BSCB model. In the present study, we established a microvascular endothelial cell line derived from a rat spinal cord and characterized this new model. Methods A conditionally immortalized cell line, termed rBSCB ‐1, was established by introducing the temperature‐sensitive SV 40 large T ‐antigen gene into primary microvascular endothelial cells isolated from a rat spinal cord. We examined whether this model retains barrier‐specific properties. Results The rBSCB ‐1 expressed several basic endothelial cell markers and the large T ‐antigen, and showed temperature‐dependent cell growth and barrier function. They also expressed tight junction molecules including claudin‐1, 3, 5, 12, occludin, zonula occludens ( ZO )‐1 and barrier‐specific transporters. The rBSCB ‐1 showed low paracellular permeability to 4 kD a dextran and high transport activity of P ‐glycoprotein. In addition, the treatment with astrocytic factors increased the barrier properties of rBSCB ‐1, including their expression levels of tight junctional molecules. Conclusion The rBSCB ‐1 cells are the first conditionally immortalized endothelial cell line derived from the BSCB that have been fully characterized as barrier‐forming cells. This cell line should be a useful tool to understand the BSCB disruption involved in many neurological disorders including multiple sclerosis and spinal cord injury.