Grant: Project Grant

About ~80,000 Canadians live with spinal cord injury (SCI). There is no cure for SCI and it can result in the loss of sensation, muscle use and organ function below the lesion. SCI typically severs fine nerve cell processes in the spinal cord. These fine processes are called axons and do not naturally regrow. Interventions are needed to promote axon growth, to remove scar tissue formation and to guide axon growth across the spinal cord lesions that can be several cm long in humans. This proposal leverages a less commonly explored approach for SCI repair involving light stimulation, combined with well-established and promising techniques for spinal cord injury repair using an animal model. Since its invention in 2005, optogenetics, which genetically sensitizes nerve cells, called neurons, to light, has become a powerful tool in animal brain research to understand complex nerve cell connections, aka neural circuits, by light stimulation. However, while shown promising, its potential for axon growth has yet to be fully harnessed primarily due to technological limitations in chronic light delivery to tissues deep under the skin such as the spinal cord. We have developed small flexible light sources coupled with electronic components for long term light delivery to the spinal cord. We will perform a comprehensive study to assess the effects of light stimulation as well as scar removal by administering an established enzyme on walking recovery and axon growth after SCI in animal models. The study will then be extended to larger SCI where, it is also necessary to provide a physical bridge for the axons. The neural probes will be combined with so called axon guidance scaffolds to assess walking and axon growth across the lesion. Exploiting optogenetics enables targeting specific neurons. Stimulating or inhibiting different neuronal cell types via optogenetics will aid in the future discovery of functional repair mechanisms to eventually develop a therapy for SCI.