Magnetic resonance imaging of transplanted oligodendrocyte precursors in the rat brain

THE lack of any markers for oligodendrocyte precursors that can be visualiz ed within the intact CNS is a significant barrier to trials of transplantat ion of these cells which aim to enhance remyelination in multiple sclerosis . We have therefore asked whether dextran-coated superparamagnetic iron oxi de (SPIO) can be used to label cells prior to transplantation and then visu alized within the brain using MRI. We have shown that an oligodendrocyte pr ecursor cell line CG-4 will take up dextran-coated SPIO particles in vitro. The label remains within the cells after transplantation into adult rat br ain, as assessed by electron microscopy, and is visible by MRI as a reducti on in signal intensity at the transplant site at both 1 and 7 days after su rgery. We conclude that MRI detection of SPIO-labelled cells represents a p romising and novel approach to the analysis of oligodendroglial cell behavi our following transplantation that has very significant advantages over cur rently available methods. (C) 1999 Lippincott Williams & Wilkins.