Astrocytes are star-shaped glial cells that perform multiple functions including support of the blood-brain barrier, provision of nutrients to neurons, and maintenance of extracellular ion balance. During a glial reaction, reactive astrocytes undergo hypertrophy and upregulate intermediate filament proteins such as GFAP (glial fibrillary acidic protein). They form a glial scar that helps to isolate the damaged area but can also inhibit axonal regeneration.
