Astrogliosis (also known as astrocytosis or referred to as reactive astrocytosis) is an abnormal increase in the number of astrocytes due to the destruction of nearby neurons from CNS trauma, infection,  ischemia, stroke, autoimmune responses, and neurodegenerative disease. In healthy neural tissue, astrocytes play critical roles in energy provision, regulation of blood flow, homeostasis of extracellular fluid, homeostasis of ions and transmitters, and regulation of synapse function, and synaptic remodeling. Astrogliosis changes the molecular expression and morphology of astrocytes, causing scar formation and, in severe cases, inhibition of axon regeneration.