Experimental spinal cord injury (SCI) models have helped define levels of structural and functional plasticity within the spinal cord and affected muscles. Peripheral nerve grafts (PNGs) support the regeneration of acute and chronically injured neurons although growth beyond the graft, back into the spinal cord, is limited in terms of the number and length of axonal extension. Digestion of inhibitory proteoglycans with Chondroitinase is partially effective in increasing axonal outgrowth and there is evidence of functional synaptic connection between regenerated axons and spinal cord neurons. Exercise-induced increase of neurotrophic factors in thoracic and lumbar spinal cord is correlated with the restoration of motoneuron excitability (spinal reflexes) to near normal activity. Despite these successes there remain thousands of injured neurons that are not involved in reorganization and repair of the injured spinal cord. Our objectives are to address mechanistic questions related to the potential for exercise to provide trophic factor cues to potentially promote the regenerative response of injured neurons and/or to activate spinal networks to facilitate receptivity of regenerating axons.
Aim 1 will address the hypothesis that exercise will promote regeneration of acute and/or chronically injured axons into a PNG, using an adult rat lower thoracic level transection injury, separate PNGs to support growth of descending vs. ascending axons and treadmill step training. Tract tracing methods will define the regenerative effort of motor and sensory neurons.
Aim 2 will test whether exercise increases axonal outgrowth from a PNG and determine possible functional improve- ment related to regenerated axons by performing sensorimotor behavior, kinematic and electrophysiological analyses. In separate groups we will test whether activity-dependent plasticity is achieved with either/or an acute or delayed treatment approach. To advance the preclinical translation of our treatment strategy, results from SCI rats will be applied to a spinalized cat preparation to test whether exercise and transplantation promote regeneration-based functional recovery in a large animal model. Overall, these experiments will provide fundamental information about cellular and functional aspects of spinal cord reorganization in acute and chronic stages of SCI that will be instrumental in designing strategies for repair.
Here we will combine transplantation and exercise treatment strategies to determine if the regenerative effort of injured neurons can be enhanced in acute and chronically injured animals. This observation directiy impacts the overwhelming number of spinal cord injured patients because of the perception that most surgical interventions should be delayed until the individual is stable and opportunities for spontaneous recovery have subsided.
|Twiss, Jeffery L; Fainzilber, Mike (2016) Neuroproteomics: How Many Angels can be Identified in an Extract from the Head of a Pin? Mol Cell Proteomics 15:341-3|
|Detloff, Megan Ryan; Quiros-Molina, Daniel; Javia, Amy S et al. (2016) Delayed Exercise Is Ineffective at Reversing Aberrant Nociceptive Afferent Plasticity or Neuropathic Pain After Spinal Cord Injury in Rats. Neurorehabil Neural Repair 30:685-700|
|Sachdeva, Rahul; Farrell, Kaitlin; McMullen, Mary-Katharine et al. (2016) Dynamic Changes in Local Protein Synthetic Machinery in Regenerating Central Nervous System Axons after Spinal Cord Injury. Neural Plast 2016:4087254|
|Jin, Y; Bouyer, J; Shumsky, J S et al. (2016) Transplantation of neural progenitor cells in chronic spinal cord injury. Neuroscience 320:69-82|
|Sachdeva, Rahul; Theisen, Catherine C; Ninan, Vinu et al. (2016) Exercise dependent increase in axon regeneration into peripheral nerve grafts by propriospinal but not sensory neurons after spinal cord injury is associated with modulation of regeneration-associated genes. Exp Neurol 276:72-82|
|Yuan, Xiao-bing; Jin, Ying; Haas, Christopher et al. (2016) Guiding migration of transplanted glial progenitor cells in the injured spinal cord. Sci Rep 6:22576|
|Twiss, Jeffery L; Kalinski, Ashley L; Sachdeva, Rahul et al. (2016) Intra-axonal protein synthesis - a new target for neural repair? Neural Regen Res 11:1365-1367|
|Hayakawa, Kazuo; Haas, Christopher; Fischer, Itzhak (2016) Examining the properties and therapeutic potential of glial restricted precursors in spinal cord injury. Neural Regen Res 11:529-33|
|Jin, Ying; Bouyer, Julien; Haas, Christopher et al. (2015) Evaluation of the anatomical and functional consequences of repetitive mild cervical contusion using a model of spinal concussion. Exp Neurol 271:175-88|
|Hayakawa, Kazuo; Haas, Christopher; Jin, Ying et al. (2015) Glial restricted precursors maintain their permissive properties after long-term expansion but not following exposure to pro-inflammatory factors. Brain Res 1629:113-25|
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