Deciphering glial scar after spinal cord injury

Spinal cord injury (SCI) often leads to permanent disability, which is mainly caused by the loss of functional recovery. One of the reasons for this interruption is the formation of a glial scar around the severely damaged tissue, which is usually covered by reactive glia, macrophages and fibroblasts. The formation and impact of glial scars have been studied thoroughly in SCI, and glial scars are formed after cortical injury, ischemic brain injury or neuron inflammation. Glial scars mainly consist of two parts: a border line and a lesion core. Elucidation of the causes of glial scar formation and identification of the cell components involved and the related regulatory mechanisms may help regulate post-SCI scar formation and promote axon regeneration.

• 1
  Microglia are an important component of the protective scar that forms after SCI. Microglia form a dense cellular interface between reactive astrocytes and infiltrating monocyte-derived macrophages at the border of the lesion post-SCI.
• 2
  After SCI, the ependymal cells are activated, exhibit stem/progenitor cell properties and generate scar-forming astrocytes. Minimal SCI can induce an endogenous ependymal cell response where ependymal cells proliferate and migrate, differentiating primarily into astrocytes.
• 3
  SCI can induce a significant fibroblast response that produces matrix components. The resulting matrix components directly inhibit nerve regeneration and promote prolonged tissue remodeling through interactions with inflammatory cells.