[The 14th International Symposium: MOLECULAR BASIS OF PATHOLOGY AND THERAPY IN NEUROLOGICAL DISORDERS].

The 12 th International Symposium " Molecular basis of pathology and therapy in neurological disorders " Investigations of the factors influencing mammalian axonal growth and regeneration are currently addressed using a range of in vitro and in vivo models. The in vitro models often employ relatively simple 2D culture systems (or the more recent development of axon diodes in micro-fluidics [5,6]) and present the advantage of ready access, manipulation and visualization of the axons and the environment in which they are growing. The in vivo models employ relatively expensive laboratory animals and present the advantage of studying axon growth in a more natural 3D environment of supporting cells and extracellular matrix. Our earlier in vitro attempts to demonstrate the support of axon regeneration by 3D bio-engineered scaffolds involved the use of explanted dor-sal root ganglia (DRG) obtained from adult rats [2,3]. This approach has been useful for demonstrating the influence of the scaffold on the properties of glial cell adhesion, proliferation , migration and process extension as well as on axon regeneration and orientation of growth. However, such studies were limited sensory neurons which are easy to dissect and can be maintained in culture for extended periods of time. However, patterns of DRG axonal growth do not necessarily reflect those that may be demonstrated would be expected by motor axons: differences in axonal growth between the motor and sensory neurons (in both in vivo and in vitro models) have been demonstrated by others in response to specific cellular and molecular cues, including differences when presented with environments containing a range of growth factors [1]. Such differences highlight the value of assays capable of evaluating neuron subtype-specific responses to their environment. Here, we describe the use of the in vitro organotypic spinal cord slice preparation for the investigation of motor axon regeneration from early post natal (P7-P9) rat pups and demonstrate the influence of scaffold microstructure on the trajectories the axons (for a complete description see Gerardo-Nava and colleagues [4]). To date, in vitro investigations of such motor axon-3D scaffold interactions remain poorly characterized, largely due to the difficulties of culturing motor neurons (MN) for extended periods in vitro. The organotypic spinal cord slice preparation has the advantage of studying motoneurons in a relatively normal cellular niche of the ventral horn gray matter in which their survival and axonal regeneration can be maintained for many weeks or even months. The rat …