Two project grants from the NC3Rs have allowed Professor Hugh Perry, from the University of Southampton, to design a multi-chamber device for studying neural degeneration with co-investigator Dr Tracey Newman. The novel bioengineering solution has the potential to enable the reduction of rodents used in neurodegeneration studies.
Principal Investigator: V. Hugh Perry, Professor of Experimental Neuropathology
Co-Investigator: Tracey Newman, Lecturer in Clinical Neurosciences
Organisation: University of Southampton
Award: £181,068, in 2006, over 24 months; £210,884, in 2009, over 24 months
Titles: In vitro multi-chamber systems for studying neural degeneration processes; A compartmentalised chamber for the in vivo study and manipulation of axon degeneration
Read more about Professor Perry's research
Neurodegeneration occurs in many diseases affecting the central nervous system
Neurodegeneration is a component of many neurological disorders including multiple sclerosis, stroke and Alzheimer’s and Parkinson’s diseases. Understanding how to protect neurons from injury and death is a key area of research for new therapies. Neurons can be divided into three sub-cellular compartments – the cell body, axon and dendrites, each residing in a different microenvironment. Recent research has shown that degeneration of the cell body, axon and dendrites occurs by different mechanisms.
Better in vitro systems would reduce the use of animals in neurodegeneration research
Studying the cellular and molecular changes that occur during neurodegeneration often involves the use of rats and mice; it is estimated that worldwide 120,000 animals are used in invasive studies and 10,000 as a source of primary neurons for in vitro models. The utility of in vitro systems is limited by the size and polarity of neurons and the difficulty in mimicking the different microenvironments for each compartment.
Reducing the number of animals that are used requires better in vitro systems that enable the different compartments of the neuron to be manipulated and studied independently. In 2006, Professor Hugh Perry and Dr Tracey Newman, University of Southampton, were awarded NC3Rs funding to develop such a system, with additional funding provided in 2009 to support scale-up and testing.
A bioengineering solution for in vitro studies
A microfluidic device comprised of two chambers has been developed. The cell bodies of the neurons reside in one chamber and the axons in the other. Axon growth can be further controlled by using thin stripes of the substrate laminin separated by polyethylene glycol so that the axons form bundles or fascicles as they would in the central nervous system. Fluids do not readily pass between the two chambers and this means that the cell body and axon can be exposed to different environments, for example, by the inclusion of other cell types or the addition of drugs to one or other chamber.
The device is the first high-throughput system that can be imaged using conventional microscopy, and is amenable to electrophysiology, transfection, and other manipulations where direct contact with the neuron is required. Neurons can be maintained for up to four weeks and are phenotypically similar to those grown using conventional in vitro techniques.
Large scale production is essential to maximise use of the device and ensure that it is commercially viable. In 2009, additional funding was provided to simplify the device construction, moving away from high technology microfabrication to a more standard tissue culture device to enable future scale-up using conventional plastic injection moulding. The detailed fabrication protocol has been made widely available. There has been one publication arising from the grant.
Identifying the earliest events after neuron injury
Professor Perry and Dr Newman are using the device to study events that occur during neuronal injury or transection. When an axon is cut or crushed a sequence of events is initiated, termed Wallerian degeneration, which include breakdown of the axonal cytoskeleton and myelin degradation. The early molecular events that underpin this are poorly understood although studies in mutant mice suggest that it may be possible to slow and modulate neurodegeneration. Using proteomic analyses, Professor Perry and Dr Newman have shown that remodelling of the actin cytoskeleton is one of the earliest detectable changes after axon injury, and that this change may be controlled intrinsically by the axon. The new device is being used to investigate this further, including by pharmacological modulation.
This case study was published in a review of our research portfolio in November 2013.