Table 1.

Positive and negative effects of the glial scar.

Positive Effects:	References:
Uptakes excess glutamate preventing chronic glutamate neurotoxicity	[70,71]
Macrophages improve overall tissue quality through removal of cell debris	[43,55,57]
Prolonged tissue repair signaling	[16,36,49]
Maintains body’s natural excitation/inhibition ratio; helps prevent irregular signaling	[45,72,73]
Physical barrier to protect remaining functional tissue	[14,29,37]
Negative Effects:
Non-resolving auto-immune response that leads to fueling fibrosis; over stimulation of inflammation leads to damaged surrounding tissues	[16,74]
Over stimulation of inflammation leads to damaged surrounding tissues	[16,50,75]
Inhibits differentiation of OPCs	[26,76]
Inhibits axogenesis, plasticity of the neuron, and myelin generation	[4,5,6,13,77]
Physical barrier making transplanted/endogenous cell migration difficult	[29,35,45,78]
Excessive production of free radicals, reactive oxygen species (ROS), and glutamate, as well as ion imbalance	[14,79,80,81]