Fig. 1.

Cellular constituents of the glial/fibrotic scar. Following spinal cord injury, pro-inflammatory cascades activate the multitude of cells found at the spinal cord lesion. The glial scar itself is composed of astrocytes, NG2 + oligodendrocyte progenitor cells, and microglia, among others. Astrocytes and oligodendrocyte progenitor cells of the lesion penumbra are especially important in remodeling the extracellular matrix and upregulating axon-inhibitory chondroitin sulfate proteoglycans (CSPGs). Cells of the lesion penumbra work in concert to cordon off the pro-inflammatory lesion epicenter. The lesion epicenter predominantly includes macrophages and fibroblasts which are sequestered to prevent the spread of inflammation after injury