Nervous system injury and disease are significant causes of mortality and morbidity. For many years research into ways of rescuing or protecting neurons from degeneration and death have focussed on the neuronal cell body. It is now recognised that degeneration of synapses or axons may also contribute to the outcome and progression of an acute brain injury or neurodegenerative disease. The discovery of the Wlds mouse showed that degeneration of axons and synapses is an active self-destructive biochemical process. The degeneration of the soma, axon and synapses occurs by different mechanisms and appears to be compartmentalised. Large numbers of animals, mostly mice and rats, have been used to model aspect of human neurological disease. These approaches have helped our understanding of the selective vulnerability of axons and synapses. Many of these models are complex, invasive and may result in significant disability of the animal. If we are to reduce or replace the numbers of animals being used to elucidate the molecular basis of axon degeneration we need better in vitro protocols. Axons and their cell somas reside in different microenvironments. Experimental protocols where the axon and its environment may be manipulated independently of the cell soma are needed. We have developed a system that allows proteins to be precisely stamped onto a surface to provide a substrate for axons to grow in oriented fascicles. We now propose to develop a compartmentalised chamber system using soft lithography and microfabrication techniques, using polymer-based materials that will permit the cell soma to be isolated from the axon and for the axon to grow in directed fascicles in parallel stripes across the culture system. The system will be optimised for fluid control between the two compartments and for the organisation of the axon fascicles to enable them to be individually damaged or manipulated. To encourage the neuroscience community to adopt this approach to reduce and replace in vivo experiments we need to demonstrate its utility. We will take advantage of our recent findings demonstrating that early changes in actin treadmilling are involved in axon degeneration and that polymerisation of axonal actin may be protective. Using a pharmacological approach we will modify actin polymerisation in axons independently of the cell soma and show that this is neuroprotective. Compartmentalised chambers will permit researchers to analyse the degeneration of distinct compartments of the neuron and reduce and replace in vivo animal experimentation.
Arundell M et al (2011). Integration of a macro/micro architectured compartmentalised neuronal culture device using a rapid prototyping moulding process Lab Chip 11:3001-3005. doi: 10.1039/C1LC20120D