The inability of axons to regenerate and reinnervate after trauma and disease, such as spinal cord injury (SCI), stroke, traumatic brain injury (TBI), or multiple sclerosis (MS), results in a devastating prognosis for patients [1-3]. Numerous studies have identified two broad classes of axon growth inhibitor (AGI) proteins which are responsible for axon growth arrest . These are, namely, myelin associated inhibitors (Nogo, MAG, OMgp) and the Chondroitin Sulfate Proteoglycans (CSPGs). Experiments that negate the activity of these inhibitors in vivo have shown a slight increase in regeneration of damaged axons, but a more dramatic restitution of function . An alternative hypothesis to “long-distance” axon regeneration-mediated restitution of function would be the reorganization of intact spinal circuitry that often remains after SCI . One of the goals of such experiments is to evaluate the potential for intact spinal circuits to replace lost connections and further to define whether negating the actions of AGIs supports adaptive or maladaptive axonal reorganization.
In this study, both widefield microscopy and the THUNDER imaging technology were used. The goal was to see if there is a difference in efficiency for screening of active versus non-active axons.
A mouse model organism was used for the study. Fluorescently labeled mouse spinal cord sections were harvested. Counting active axons in areas treated with injections that negate the actions of AGI’s was used to determine the efficacy of the experimental treatment.