Magnetic Resonance Molecular Imaging of Neural Sprouts in Spine Explant Cultures

Introduction: There are several spinal cord injury models available for studying axonal repair in vivo [1] however, these studies are restricted to functional or behavioural changes [2] or tissue level pathologic changes detectable by MRI [3] and by histology [4]. In vitro models that use dissociated neurons provide useful information about extrinsic factors and substrates that promote neural cell differentiation and neural sprouting but are of limited value in studies of axonal regeneration. In contrast, organotypic slice cultures of spinal cord allow for the study of axonal growth and regeneration, synapse formation, and myelination [5]. Consequently, to better understand the dynamics of spinal cord repair in vivo, we used spinal cord explant cultures to test the specificity of actin-targeted Gd-liposomes to actin-rich neural sprouts. This model system provides a novel test platform for the development of MR molecular imaging probes for the study of unique cell populations, synapse formation, and axonal regeneration in models of spinal cord repair.