Electronic Thesis and Dissertation Repository


Master of Science




Dr. Arthur Brown


Many individuals who have suffered from spinal cord injury (SCI) have longstanding damage. The molecular environment of the spinal cord is not permissive to axonal growth and neuroplasticity after injury is limited. Perineuronal nets containing chondroitin sulfate proteoglycans (CSPGs) are major inhibitors of axonal sprouting. Our laboratory has identified that the transcription factor SOX9 regulates a battery of genes involved in CSPG biosynthesis. Using Sox9 conditional knockout mice, we have shown that ablating Sox9 before injury decreases CSPG levels in the cord, increases reparative sprouting, and leads to improved locomotor recovery. However, it is unknown whether Sox9 ablation following SCI leads to similar recovery. To investigate this, Sox9 was ablated in mice 30 days after SCI. This ablation did not decrease levels of perineuronal nets, increase neuroplasticity or improve locomotor recovery compared to controls. These results will be discussed in the context of CSPG turnover rate and matrix metalloproteinase activity.