HOUSING CONDITIONS EFFECT ON SPINAL CORD REGENERATION POST SPINAL CORD INJURY IN LARVAL ZEBRAFISH

Abstract

Spinal cord injury (SCI) is a major public health burden. There is currently no cure for SCI and up to 30% of people with SCI will develop anxiety. Regenerative models, like the zebrafish, may be our best resource for finding new treatments. Our lab previously demonstrated that when given a food source that is alive and moves (rotifers), a larger percentage of larval zebrafish form a complete glial bridge and recover motor skills after SCI than larvae given a pellet diet. However, it was unclear whether increased motor recovery was from a difference in nutrition or the visual stimulation of moving prey. In addition, whether the zebrafish exhibited anxiety-like behavior after SCI and during recovery, particularly in the presence of live food, was never determined. In this study, we tested how housing conditions, larvae individually housed or housed together, affect anxiety and locomotor activity in uninjured larvae. In addition, we were able to test whether spinal cord regeneration via glial bridging post SCI was affected by these different housing conditions. The visual motor response test (VMRT) was used as a metric to measure thigmotaxis and locomotor activity. Live imaging was utilized to measure whether a complete glial bridge was formed or not in injured larvae. Measuring both total swim and thigmotaxis (an anxiety assay for larval zebrafish), we observed no difference in % thigmotaxis between housing conditions for uninjured animals. However, total swim increased with time when placed in a group housed environment. Further, we found that glial bridging was increased when larvae with SCI were placed in a group housed environment suggesting that housing conditions can enhance pro-regenerative outcomes.